Electronic Material Properties - und Geowissenschaften ...

ANNUAL REPORT
2 0 0 6
FACULTY OF
MATERIALS- AND GEO-SCIENCES
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ANNUAL REPORT
2 0 0 6
FACULTY OF
MATERIALS- AND GEO-SCIENCES

Annual Report
2006
Faculty 11
Materials- and Geo-Sciences
Materials Science:
Petersenstraße 23 • L2 01 • 64287 Darmstadt
Phone: +49 (0) 6151 / 16 - 5377 • Fax: +49 (0) 6151 / 16 - 5551
http://www.tu-darmstadt.de/fb/ms/
Applied Geosciences:
Schnittspahnstraße 9 • B2 01/02 • 64287 Darmstadt
Phone: +49 (0) 6151 / 16 - 2571 • Fax: +49 (0) 6151 / 16 - 6539
http://www.tu-darmstadt.de/fb/geo/
For further information contact:
Dr. Joachim Brötz, Phone: +49 (0) 6151 / 16 - 4392; eMail: broetz@tu-darmstadt.de
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Contents
I. PREFACE 4
II. INSTITUTE OF MATERIALS SCIENCE 8
Physical Metallurgy.................................................................8
Ceramics Group ...................................................................15
Electronic Material Properties...............................................19
Surface Science ...................................................................23
Thin films ..............................................................................28
Dispersive Solids ..................................................................31
Structure Research...............................................................36
Chemical Analytics ...............................................................44
Theoretical Materials Science ..............................................49
Materials Modelling...............................................................52
Materials for Renewable Energies........................................54
Joint Research Laboratory Nanomaterials ...........................56
Collaborative Research Center (SFB) ..................................58
Reports of Research Activities 61
Diploma Theses 110
PhD Theses 112
Mechanical Workshop 113
III. INSTITUTE OF APPLIED GEOSIENCES 114
Physical Geology and Global Cycles..................................114
Hydrogeology .....................................................................117
Engineering Geology ..........................................................118
Applied Sedimentology.......................................................122
Geo-Resources and Geo-Hazards .....................................125
Geomaterials Science ........................................................128
Technical Petrology ............................................................131
Environmental Mineralogy ..................................................135
Reports of Research Activities 137
Diploma Theses 161
Magister Theses 161
PhD Theses 161
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Preface
The year 2006 of the Department of Materials- and Geo-Sciences was characterized by a
stabilisation of the Geo-Sciences and a shift of severe structural changes to the Institute of
Materials Science. In addition, our Dean Prof. Heinz von Seggern resigned due to health
problems on March 31 and was succeeded by Prof. W. Jaegermann. We all would like to
thank Prof. v. Seggern for his efforts. Finally, the target agreement was signed mid of
2006; however some different opinions on the future of the departments were still not
settled at this time. The development of students’ and graduate numbers for Materials- and
Geo-Science are shown in Fig. 1.
Fig. 1 Number of graduates (diplomas and doctorates) in Materials- and Geo-Sciences at
Darmstadt University of Technology over the last 7 years
After the appointment of Prof. Hans-Joachim Kleebe in January 2006 as head of the
Geomaterials Group following Prof. Wolfgang Müller, all chairs of the Institute of Geo-
Science are now assigned. The new crew has defined new directions in research and
education at the TU Darmstadt. More information about the achievements of the year 2006
are given below.
In Materials Science the reoccupation of professorships substituting the first founding
generation after retirement or appointment to other institutions is still a major challenge.
Hartmut Fuess who was the first professor of the newly founded Department of Materials
Science in 1989 was retired in Oct. 2006. Prof. Dr. Dr. h. c. Fuess was head of the
Structural Research Division and succeeded to built-up a nationally and internationally
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highly recognized research lab on structural research. Especially, the powder diffraction
facilities located at national laboratories in Hamburg and Munich (DESY and FRM II) were
used in cooperation by many guests from Germany and other institutions abroad. In
addition, Prof. Fuess served for several years as dean of the Department of Materials
Science and after unification with Geoscience of the Department of Materials- and Geo-
Sciences. He has strongly contributed to the excellent scientific profile of the department
by his outstanding scientific contributions, but also by his visionary ideas and admirable
management qualities. We will have to struggle hard to find qualified successors.
Fortunately Prof. Fuess has agreed to continue to lead his research group for the next
future until a successor has joined the department. Therefore we still profit from his
experience and knowledge. In September 2006 Prof. Jürgen Eckert followed an offer of
the Institute of for Solid State and Materials Research in Dresden as head of the
Department of Complex Solids. We would like to thank him for his contributions in
Darmstadt and wish all the best for his new appointment.
Some of the very qualified junior scientist who have obtained their habilitation at TU
Darmstadt have also left the department: Dr. Doru Lupascu moved to TU Dresden where
he was appointed as professor of functional ceramics; Dr. Roland Schmechel was
appointed as a professor in electrical engineering at University of Duisburg-Essen on
nanostructuring techniques (unfortunately we were not successful to keep him at our
institute with a combined effort of TUD and FZK); Dr. Helmut Ehrenberg has moved to the
IFW Dresden together with Prof. Eckert. We want to thank our younger colleagues for their
valuable contributions to the success of the department and hope for similarly qualified
Post-Docs in the future to secure the high level of our scientific and educational efforts.
A large fraction of time was devoted during 2006 to join the national excellence initiative
with the final application of a cluster of excellence MECAD aiming at multi-functional
materials based on composites for advanced devices. During the first months of the year
regular extended discussions on the scientific content and organisational and structural
demands were held together with our colleagues from the departments of chemistry,
physics, biology, electrical engineering and mechanical engineering. Finally, thanks to the
perfect management of Prof. J. Rödel a very promising research proposal was submitted,
which unfortunately did not receive funding at the end. However, as we have obtained
encouraging referee reports on the scientific content of our research proposal we intend to
follow this interesting topic as one of our maior scientific subjects of the future.
Fortunately, another major research program in Materials Science, the collaborative
research centre on “Electric fatigue in functional materials”, was positively evaluated in
Oct. 2006 and will continue in its second funding period. This activity is also directed by
Prof. Rödel and a special thanks goes also to Dr. Kinski who provided substantial support
in preparing the proposal consisting of more than 750 printed pages. The proposal was
rated close to excellent by the referees and will be continued nearly without any
deductions. In result, a strong support of the Materials Science research activities was
successfully realized, which will help to keep us in action for the next four years.
The annual event “Materialwissenschaftlicher Tag” in 2006 was devoted to the 60 th
anniversary of Prof. Rauh. At this occasion the research activities in Theoretical Materials
Science at our department were presented. Since Prof. Rauh is not only interested in
theoretical physics, but also in classical music, well balanced contributions of talks, posters
and musical performances of the Rauh family stimulated inspiring discussions on the
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difference of numerical and analytical theoretical approaches vs. Beethoven’s and
Mozart’s approach to well defined musical masterpieces.
Finally, we also want to announce special honours of members of our department. First of
all Prof. Riedel was honoured as Honorary Doctor (Dr. h. c.) of the Slovak Academy of
Sciences, Bratislava, Slovak Republik. The students’ price of the best MaWi student was
given to Dipl. Ing. Taek Lim followed by E. Mankel, B. Siepchen and A. Gassmann who
presented their Diploma theses during the yearly Summer Party of the Material Science
Institute. The MRS Graduate Student Gold Medal was awarded to Dr.-Ing. Paul Erhart for
this PhD-thesis on point defects in zinc oxide at the MRS Fall Meeting 2006 in Boston.
The year 2006 in the Materials Science Institute was brought to an end with the traditional
Christmas Party to which very many people contributed in a more or less active way.
Again a number of high level of art, music, and comedy performances has proven that
materials scientists have talents beyond their scientific abilities. The party was finished
again very late this year after the early visit of Father Christmas.
The Institute of Applied Geosciences finally filled all vacant positions and finished its
restructuring process by the appointment of Prof. Dr. Hans-Joachim Kleebe, who is
heading the Geomaterial Science group since January 2006. Moreover, with the retirement
of Prof. Fuess, Prof. Kleebe took over the administration and responsibility of the
transmission electron microscopy facility. Thereby, electron microscopy and x-ray
diffraction techniques are no longer in one hand. It is anticipated to strengthen the TEM
group and create a state-of-the-art electron microscopy facility which is strongly supports
research at the geo- and material science community as well as other faculty on campus.
The research focus Geothermal Energy was established by the Engineering Geology
Group of Prof. I. Sass. Geothermal energy is one of the few regenerative energy systems,
capable of providing a base load with potentially enormous resources. In July 2006, the
first Geothermal Summer School with about 50 participants was held in Darmstadt, in
cooperation with the Institute and Laboratory for Geotechnics. In addition, in cooperation
with the "Hessisches Ministerium für Wirtschaft, Verkehr und Landesentwicklung" the first
Forum on Deep Geothermal Reservoirs took place at TUD with about 150 participants.
The Hydrogeology Group together with the Applied Sedimentology Group initiated a
second new research focus on groundwater management in arid regions. In cooperation
with the GTZ, a first project was started on groundwater resources in Saudi-Arabia. We will
strengthen our efforts to play a significant role in this area as a qualitative and quantitative
approach to manage regional groundwater resources based on the principal of
sustainability is one of the crucial topics in the field of applied geosciences in the future.
In 2006 we could celebrate the award of a prestigious price to one of our young scientists.
Dr. Martin Ebert from the Environmental Mineralogy Group of Prof. Weinbruch, who
received the ‘Adolf-Messer-Award’ 2006 of the Messer Foundation for his groundbreaking
research on atmospheric aerosols and their importance for climate and health. The award
was presented to Martin Ebert in a ceremony by Stefan Messer, owner and CEO of the
Messer Group. We congratulate Martin Ebert on his achievement and the attention his
research has attracted.
Our International Master Course TropHEE (Tropical Hydrogeology, Engineering Geology
and Environmental Management) started in October 2006 with the enrollment of the first
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students. TropHEE is internationally accredited and certified, and designed for
geoscientists (geologists, geoecologists, geophysicists, mineralogists, geographers, soil
scientists, civil engineers) who wish to obtain a wide range of knowledge in hydrogeology,
engineering geology and environmental management with a special emphasis on tropical
and subtropical regions. There are 10 scholarships for TropHEE available every year and
we are expecting about 20 students per year.
As it is the tradition in Geosciences to conclude the year with the ‘Barbara Fest’, all faculty,
staff and students got together to discuss the events of the year as well as the future in a
very friendly and positive atmosphere.
The outcome and most remarkable results of research in 2006 are summarized below for
the different divisions and working groups of the Department of Materials- and Geo-
Science. These results would not have been possible without the strong engagement and
outstanding efforts of all people in the department ranging from our excellent workshop
headed by J. Korzer, to the technical and administrative staff in the research groups, the
students, Diploma students, Ph.D. students and last but not least to the PostDocs in the
different research groups. We would like to thank all of them for their valuable
contributions and hope that it will be possible to keep the excellent working atmosphere for
the upcoming years.
Wolfram Jaegermann
Dean of the Faculty of Materials- and Geo-Sciences
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Institute of Materials Science
Physical Metallurgy
The activity of the Physical Metallurgy Division covers a broad range of research on
structural and functional metallic materials, starting from the basic processes and
mechanisms governing metastable phase formation upon quenching from the melt as well
as solid state processing, including detailed microstructure investigations and structure
analysis ending with the description of the performance of components in technical
applications. Special attention is paid to understand the correlation between phases,
microstructure and physical properties of the material, also when considering the effect of
processing conditions on materials properties during and after rapid quenching, casting,
mechanical alloying / ball milling, powder consolidation, heat treatment, as well as shaping
and forming operations. The ultimate goal is to use this understanding to tailor new or to
optimize customized materials with improved properties for applications. The research is
thus spanning from basic scientific questions to technological research and development
efforts. Besides experimental work, also model-based property descriptions including
casting processes, coarsening and recrystallization, forging, sheet drawing and chip
formation, as well as microstructure-based modelling of mechanical properties are
performed. This allows to propose guidelines for further property optimization.
The materials under investigation are titanium-, magnesium-, and aluminium-based light
alloys, steels, multicomponent glass-forming alloys, and nanostructured/ ultrafine-grained
alloys. Their microstructure development and deformation behavior under different loading
conditions and the interaction with environmental conditions like corrosive media are
investigated. In 2005 progress in the area of microstructure-based processing for
properties was achieved in the fields of titanium alloys for various functional and structural
applications and novel nanostructure-dendrite or glassy matrix composites, which combine
high strength with large plastic deformability. The understanding of the basics of
solidification and mechanically driven phase transitions promises to lead to optimization of
alloys for a variety of applications.
The activities focussing on the improvement of the mechanical properties of metallic
materials are complemented by work related to the development of nanostructured
materials for use as functional materials with interesting properties for magnetic
applications, catalysis, hydrogen storage or as electrode materials. Again, this includes
structural investigations that provide the basis for the understanding of the physical
properties of such materials. For example, high-resolution scanning and transmission
electron microscopy combined with x-ray scattering techniques and magnetic or
electrochemical measurements allows to describe the nanostructure formation, gives
insight into the nature of structural inhomogeneities and helps to understand the resulting
physical properties of the materials.
The teaching activities cover basics of phase formation and stability (phase diagrams and
phase transitions, solidification behavior of materials), the mechanical properties of
engineering materials and the fundamentals of deformation and fracture as well as
quantitative microstructure analysis. Seminars and extensive laboratory exercises
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complement the lectures and help to intensify the understanding in these topics and to
improve the practical skills for investigating metallic materials.
The Physical Metallurgy Division has a variety of collaborations with the other groups in
the Institute and with other Departments at Darmstadt University of Technology (e.g.,
Mechanical Engineering, Chemistry, Physics). A special feature of the group is its strong
emphasis on national and international collaboration. It cooperates with more than 15
groups in Germany, Europe (e.g. Denmark, France, Italy, Spain, Poland, Romania, Slovak
Republic, Switzerland, UK etc.) and worldwide (USA, Canada, Australia, China, India,
Japan, Korea, Russia, Ukraine and others). Besides, strong interactions with companies
(e.g. Adam Opel AG, Daimler-Chrysler, EADS, Heraeus, Liquidmetal Inc., Umicore etc.)
exist. Participation in conferences, seminars and workshops aids the actuality of teaching
and research, fosters collaborations and promotes the exchange of students and
scientists.
Staff Members
Head Prof. Dr.-Ing. Jürgen Eckert
Research Associates Prof. Dr. Mariana Calin PD Dr. Clemens Müller
Dr. Ki Buem Kim Dr. Mihai Stoica
Technical Personnel Ulrike Kunz Petra Neuhäusel
Heinz Lehmann Claudia Wasmund
Secretary Christine Hempel
PhD Students M. Tech. Jayanta Das Dipl.-Ing. Simon Pauly
Dr. Cécilie Duhamel Dipl.-Ing. Mira Sakaliyska
Dipl.-Ing. Thorsten Keller Dipl.-Chem. Sergio Scudino
Dipl.-Ing. Arne Kriegsmann M. Tech. Shankar
Venkataraman
Diploma Students Tilman Bohn Flora Paturaud
Udo Depner Simon Pauly
Alexander Elsen René Richter
Frank Ettingshausen Jan-Michael Rudnig
Martin Frommherz Sascha Sager
Falko Langbein Sebastian Sperling
Guest Scientists Dr. Tatiana Chernova
Dr. Wei Xu
Dr. Peng Yu
Dr. Lai-Chang Zhang
Dr. Wen-Yong Zhang
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Research Projects
Bulk Amorphous Al-Alloys by Ball Milling and Spark-Plasma-Sintering (DFG, 2005-2006)
Bulk Zr-Glasses (DFG, 2004-2006)
Complex Metallic Alloys (EU Network of Excellence, 2004-2008)
DAAD Research Stipend for Dr. T. Chernova, University of Samara, Russia
Deformation Behaviour of Zr-based Metallic Glass and Metallic Glass Composites at
Elevated Temperatures (DFG, 2005-2006)
Ductile Bulk Metallic Glass Composites* (EU Research Training Network 2003-2007)
Glass-forming Ability of Ti-base Metallic Glasses (AvH, 2005-2006)
Improvement of wear resistance by roller burnishing (AIF-EFB, jointly with Prof. Groche,
2006-2008)
In-situ Formed Zirconia- and Alumina-toughened Zr-based Bulk Metallic Glasses (AvH,
2005-2006)
Influence of Shot Peening on Fatigue and Corrosion of the Mg-Alloys AZ91 and AZ80
(2002-2006)
Intensive Program for Transfer of Knowledge to Eastern European Reference Pole for
Micro- and Nanotechnologies NANOTEC-EST (EU 2005-2009)
Investigation and Preparation of Amorphous or Nanocrystalline Ribbons for Soft Magnetic
Coils in Accelerators (GSI, jointly with Prof. Hahn, 2004-2006)
Magnetic Hardening Mechanisms of Bulk Fe3B-based Nanocomposite Magnets Produced
by Crystallization of Nd-Dy-Fe-Co-B Metallic Glass (AvH, 2005-2006)
Microstructure and Mechanical Properties of Linear Flow Splitted Sheets (DFG-SFB, 2005-
2009)
Microstructure Control of Novel Ti-based Nanocomposites with Potential for Biomedical
Applications (AvH, 2005-2006)
Nd-base Alloys (DFG, 2001-2007)
Radiation-Induced Material Changes of NbTi-Superconductors (GSI, jointly with Prof.
Fueß, 2004-2006)
(* managed via the Leibniz-Institute for Solid State and Materials Research Dresden)
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Publications
Kumar, G.; Filip, O.; Löser, W.; Schultz, L.; Eckert, J.; Cooling Rate Controlled
Microstructure and Magnetic Properties of Fe20Nd80 Alloys, Intermetallics 14 (2006) 47.
Slipenyuk, A.; Kuprin, V.; Milman, Y.; Goncharuk, V.; Eckert, J.; Properties of P/M Processed
Particle Reinforced Metal Matrix Composites Specified by Reinforcement Concentration and
Matrix-to-Reinforcement Particle Size Ratio, Acta. Mater. 54 (2006) 157.
Liu, L. F.; Dai, L. H.; Bai, Y. L.; Wei, B. C.; Eckert, J.; Characterization of Rate-Dependent
Shear Behavior of Zr-based Bulk Metallic Glass Using Shear Punch Testing, J. Mater.
Res. 21 (2006) 153.
Kim, K. B.; Das, J.; Baier, F.; Tang, M. B.; Wang, W. H.; Eckert, J.; Heterogeneity of a
Cu47.5Zr47.5Al5 Bulk Metallic Glass, Appl. Phys. Lett. 88 (2006) 051911.
Kim, K. B.; Warren, P. J.; Cantor, B.; Eckert, J.; Structural Evolution of Nano-Scale
Icosahedral Phase in Novel Multicomponent Amorphous Alloys, Phil. Mag. 86 (2006) 281.
Scudino, S.; Eckert, J.; Breitzke, H.; Lüders, K.; Schultz, L.; Influence of Ball Milling on
Quasicrystal Formation in Melt-Spun Zr-Based Glassy Ribbons, Phil. Mag. 86 (2006) 367.
He, G.; Eckert, J.; Hagiwara, M.; Mechanical Properties and Fracture Behavior of the
Modified Ti-Base Bulk Metallic Glass-Forming Alloys, Mater. Lett. 60 (2006) 656.
Mudali, U. K.; Kühn, U.; Eckert, J.; Schultz, L.; Gebert, A.; Corrosion Behaviour of
Zirconium-Based Bulk Metallic Glasses, Trans. Indian Institute of Metals 59 (2006) 123.
Venkataraman, S.; Stoica, M.; Scudino, S.; Gemming, T.; Mickel, C.; Schultz, L.; Eckert,
J.; Revisiting the Cu47Ti33Zr11Ni8Si1 Glass-Forming Alloys, Scripta Mater. 54 (2006) 835.
Sun, B. B.; Sui, M. L.; Wang, Y. M.; Li, Y.; He, G.; Eckert, J.; Ma, E.; Bulk Ti-Based In Situ
Nanocomposite with High Strength and Tensile Ductility, Acta Mater. 54 (2006) 1349.
Venkataraman, S.; Scudino, S.; Eckert, J.; Gemming, T.; Mickel, C.; Schultz, L.; Sordelet,
D. J.; Nanocrystallization of Gas Atomized Cu47Ti33Zr11Ni8Si1 Metallic Glass, J. Mater. Res.
21 (2006) 597.
Yu, P.; Kim, K. B.; Das, J.; Baier, F.; Xu, W.; Eckert, J.; Fabrication and Mechanical
Properties of Ni-Nb Metallic Glass Particle-Reinforced Al-Based Metal Matrix Composite,
Scripta Mater. 55 (2006) 1445.
Kim, K. B.; Warren, P. J.; Cantor, B.; Eckert, J.; Enhanced Thermal Stability of the
Devitrified Nano-Scale Icosahedral Phase in Novel Multicomponent Amorphous Alloys, J.
Mater. Res. 21 (2006) 823.
Scudino, S.; Stoica, M.; Mattern, N.; Breitzke, H.; Lüders, K.; Yavari, A. R.; Eckert, J.; Is a
Particular Quenched-In Short-Range Order Necessary for Quasicrystal Formation from
Glassy Precursors?, Phys. Stat. Sol. (b) 243 (2006) R34.
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el Dsoki, C.; Landersheim, V. ; Kaufmann, H.; Bruder, T.; Krug, P.; Bohn, T.; Müller, C.;
Zyklisches Werkstoffverhalten sprühkompaktierter Aluminiumwerkstoffe. Kennwerte für die
Bauteilbemessung: Von der probe zum Bauteil, Mat.-wiss. u. Werkstofftech. 37, 2006,
1006-1017
Kumar, G.; Kerschl, P.; Rößler, U. K.; Nenkov, K.; Müller, K.-H.; Schultz, L.; Eckert, J.;
High-Field Magnetization and Coercivity of Hard Magnetic Mold-Cast Nd80Fe20, J. Appl.
Phys. 99 (2006) 083904.
Venkataraman, S.; Löser, W.; Eckert, J.; Gemming, T.; Mickel, C.; Schubert-Bischoff, P.;
Wanderka, N.; Schultz, L.; Sordelet, D. J.; Nanocrystal Development in Cu47Ti33Zr11Ni8Si1
Metallic Glass Powders, J. Alloys & Compounds 414 (2006) 162.
Scudino, S.; Das, J.; Stoica, M.; Kim, K. B.; Kusy, M.; Eckert, J.; High Strength Hexagonal
Structured Dendritic Phase Reinforced Zr-Ti-Ni Bulk Alloy with Enhanced Ductility, Appl.
Phys. Lett. 88 (2006) 201920.
Xu, W.; Kim, K. B.; Das, J.; Calin, M.; Eckert, J.; Phase Stability and its Effect on the
Deformation Behavior of Ti-Nb-Ta-In/Cr β Alloys, Scripta Mater. 54 (2006) 1943.
Kim, K. B.; Yi, S.; Choi-Yim, H.; Das, J.; Xu, W.; Johnson, W. L.; Eckert, J.; Effect of Cu on
Local Amorphization in Bulk Ni-Ti-Zr-Si Alloys During Solidification, Acta Mater. 54 (2006)
3141.
Venkataraman, S.; Biswas, K.; Wei, B. C.; Sordelet, D. J.; Eckert, J.; On the Fragility of
Cu47Ti33Zr11Ni8Si1 Metallic Glass, J. Phys. D: Appl. Phys. 39 (2006) 2600.
Biswas, K.; Ram, S.; Roth, S.; Schultz, L.; Eckert, J.; Fabrication of Bulk Amorphous
Fe67Co9.5Nd3Dy0.5B20 Alloy by Hot Extrusion of Ribbon and Study of the Magnetic
Properties, J. Mater. Sci. 41 (2006) 3445.
Castellero, A.; Bossuyt, S.; Stoica, M.; Deledda, S.; Eckert, J.; Chen, G. Z.; Fray, D. J.;
Greer, A. L.; Improvement of the Glass-Forming Ability of Zr55Cu30Al10Ni5 and
Cu47Ti34Zr11Ni8 Alloys by Electro-Deoxydation of the Melts, Scripta Mater. 55 (2006) 87.
Biswas, K.; Venkataraman, S.; Zhang, W. Y.; Ram, S.; Eckert, J.; Glass-Forming Ability
and Fragility Parameter of Amorphous Fe67Co9.5Nd3Dy0.5B20, J. Appl. Phys. 100 (2006)
023501.
Xu, W.; Kim, K. B.; Das, J.; Calin, M.; Rellinghaus, B.; Eckert, J.; Deformation-Induced
Nanostructuring in a Ti-Nb-Ta-In β Alloy, Appl. Phys. Lett. 89 (2006) 031906.
Kühn, U.; Eckert, J.; Schultz, L.; Annealing-Induced Phase Transitions in a Zr-Ti-Nb-Cu-Ni-
Al Bulk Metallic Glass Matrix Composite Containing Quasicrystalline Precipitates, Int. J.
Mater. Res. (formerly Z. Metallkde.) 97 (2006) 996.
Zhang, L. C.; Xu, J.; Eckert, J.; Thermal Stability and Crystallization Kinetics of
Mechanically Alloyed TiC/Ti-Based Metallic Glass Matrix Composite, J. Appl. Phys. 100
(2006) 033514.
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Kim, K. B.; Das, J.; Wu, X.; Zhang, Z. F.; Eckert, J.; Microscopic Deformation Mechanism
of a Ti66.1Nb13.9Ni4.8Cu8Sn7.2 Nanostructure-Dendrite Composite, Acta Mater. 54 (2006)
3701.
Kim, K. B.; Das, J.; Venkataraman, S.; Yi, S.; Eckert, J.; Work Hardening Ability of Ductile
Ti45Cu40Ni7.5Zr5Sn2.5 and Cu47.5Zr47.5Al5 Bulk Metallic Glasses, Appl. Phys. Lett. 54 (2006)
071908.
Kim, K. B.; Das, J.; Wang, X. D.; Zhang, X.; Eckert, J.; Yi, S.; Effect of Sn on
Microstructure and Mechanical Properties of (Ti-Cu)-Based Bulk Metallic Glasses, Phil.
Mag. Lett. 86 (2006) 479.
Exner, H.E.; Petzow, G; A Critical Assessment of Porosity Coarsening During Solid State
Sintering, Advances in Science and Technology, Vol. 45, 2006, 539 - 548
Concustell, A.; Sort, J.; Woodcock, T. G.; Gimazov, A.; Suriñach, S.; Gebert, A.; Eckert, J.;
Zhilyaev, A. P.; Baró, M. D.; Enhanced Mircohardness in Nanocrystalline
Ti60Cu14Ni12Sn4Ta10 Processed by High Pressure Torsion, Intermetallics 14 (2006) 871.
Eckert, J.; Das, J.; Kim, K. B.; Baier, F.; Tang, M. B.; Wang, W. H.; Zhang, Z. F.; High
Strength Ductile Cu-Base Metallic Glass, Intermetallics 14 (2006) 876.
Kim, K. B.; Yi, S.; Hwang, I. S.; Eckert, J.; Effect of Cooling Rate on Microstructure and Glass-
Forming Ability of a (Ti33Zr33Hf33)70(Ni50Cu50)20Al10 Alloy, Intermetallics 14 (2006) 972.
Kusy, M.; Kühn, U.; Concustell, A.; Gebert, A.; Das, J.; Eckert, J.; Schultz, L.; Baró, M. D.;
Fracture Surface Morphology of Compressed Bulk Metallic Glass-Matrix-Composites and
Bulk Metallic Glass, Intermetallics 14 (2006) 982.
Venkataraman, S.; Eckert, J.; Schultz, L.; Sordelet, D. J.; Effect of Preannealing on Glass
Transition and Crystallization of Gas Atomized Cu47Ti33Zr11Ni8Si1 Metallic Glass Powders,
Intermetallics 14 (2006) 1085.
Roth, S.; Stoica, M.; Degmová, J.; Gaitzsch, U.; Eckert, J.; Schultz, L.; Fe-Based Bulk
Amorphous Soft Magnetic Materials, J. Magn. Magn. Mater. 304 (2006) 192.
Lorenz, B.; Perner, O.; Eckert, J.; Chu, C. W.; Superconducting Properties of
Nanocrystalline MgB2, Supercond. Sci. Technol. 19 (2006) 912.
Stoica, M.; Eckert, J.; Roth, S.; Schultz, L.; Yavari, A. R.; Casting and Characterization of
Fe-(Cr, Mo, Ga)-(P, C, B) Soft Magnetic Bulk Metallic Glasses, J. Optoelectronics and
Advanced Materials 8 (2006) 1685.
Wu, F. F.; Zhang, Z. F.; Peker, A.; Mao, S. X.; Das, J.; Eckert, J.; Strength Asymmetry of
Ducticle Dendrites Reinforced Zr- and Ti-based Composites, J. Mater. Res. 21 (2006)
2331.
Zhang, Z. F.; Zhang, H.; Shen, B. L.; Inoue, A.; Eckert, J.; Shear Fracture and
Fragmentation Mechanisms of Bulk Metallic Glasses, Phil. Mag. Lett. 86 (2006) 643.
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Das, J.; Kim, K. B.; Xu, W.; Wei, B. C.; Zhang, Z. F.; Wang, W. H.; Yi, S.; Eckert, J.;
Ductile Metallic Glasses in Supercooled Martensitic Alloys, Mater. Trans. 47 (2006) 2606.
Concustell, A.; Mattern, N.; Wendrock, H.; Kühn, U.; Gebert, A.; Eckert, J.; Greer, A. L.;
Sort, J.; Baró, M. D.; Mechanical Properties of a Two-Phase Amorphous Ni-Nb-Y Alloy
Studied by Nanoindentation, Scripta Mater. 56 (2006) 85.
Kühn, U.; Eymann, K.; Mattern, N.; Eckert, J.; Gebert, A.; Bartusch, B.; Schultz, L.; Limited
Quasicrystal Formation in Zr-Ti-Cu-Ni-Al Bulk Metallic Glasses, Acta Mater. 54 (2006)
4685.
Dasgupta, S.; Das, J.; Eckert, J.; Manna, I.; Influence of Environment and Grain Size on
Magnetic Properties of Nanocrystalline Mn-Zn Ferrite, J. Magn. Magn. Mater. 306 (2006)
9.
Dasgupta, S.; Kim, K. B.; Ellrich, J.; Manna, I.; Eckert, J.; Mechano-Chemical Synthesis
and Characterization of Microstructure and Magnetic Properties of Nanocrystalline Mn1xZnxFe2O4,
J. Alloys & Compounds 424 (2006) 13.
Van Steenberge, N.; Das, J.; Concustell, A.; Sort, J.; Suriñach, S.; Eckert, J.; Baró, M. D.;
Influence of Annealing on the Microstructure and Hardness of Ti67.9Fe28.36Sn3.85
Nanocomposite Rods, Scripta Mater. 55 (2006) 1087.
Zhang, Z. F.; Wu, F. F.; Gao, W.; Tan, J.; Wang, Z. G.; Stoica, M.; Das, J.; Eckert, J.;
Shen, B. L.; Inoue, A.; Wavy Cleavage Fracture of Bulk Metallic Glass, Appl. Phys. Lett. 89
(2006) 251917.
Das, J.; Eckert, J.; Theissmann, R.; Structural Short-Range Order of the β-Ti Phase in
Bulk Ti-Fe-(Sn) Nanoeutectic Alloys, Appl. Phys. Lett. 89 (2006) 261917.
Eckert, J.; Structure Formation and Mechanical Behavior of Two-Phase Nanostructured
Materials, in: Nanostructured Materials – Processing, Properties and Potential
Applications, (Hrsg. C.C. Koch). 2 nd Edition: William Andrew Publishing, Norwich, NY, USA
(2006) 565.
Eckert, J.; Das, J.; Kim, K. B.; Nanostructured Composites: Ti-Base Alloys, in: The Dekker
Encyclopedia of Nanoscience and Nanotechnology, (Hrsg. J.A. Schwarz, C. Contescu, K.
Putyera). Marcel Dekker, Inc., New York, NY, USA (2006) DOI: 10.1081 / E-ENN-
120042102.
Eckert, J.; Scudino, S.; Yu, P.; Duhamel, C.; Powder Metallurgy of Nanostructured High
Strength Materials, in: Progress in Powder Metallurgy, (Hrsg. D.Y Yoon, S.-J.L. Kang, K.Y.
Eun, Y.-S. Kim). Mater. Sci. Forum 534-536 (2006) 1405.
- 14 -

Ceramics Group
The emphasis in the ceramics group is on the correlation between microstructure and
mechanical as well as functional properties. A number of processing methods are
available in order to accomplish different microstructure classes, to determine their specific
properties in an experiment and to rationalize these with straightforward modelling efforts.
Thereby a materials optimization is afforded, which allows effective interplay between
processing, testing and modelling. The scientific effort can be grouped as follows:
1. Sintering of oxides
Sintering of ceramics is approached using a continuum mechanical description, which
affords inclusion of laminate stresses as arise in sintering of thin films and cosintering of
several layers. In order to determine the constitutive equations for the sintering bodies,
dilatometry and a new hot forging apparatus are used. This equipment together with a
substantial modelling effort allows measurement of sintering stresses and viscosities and
thereby predictions of shrinkage and curvature in multilayer structures. From an
application points of view, thin optical layers and printed electronics are also investigated.
Materials under consideration are ZrO2, Al2O3, TiO2, ZnO as well as LTCC materials.
2. Mechanical properties of ceramics and composites:
Work on mechanical properties is geared towards an improved understanding of fracture
strength, fracture toughness, R-curve behaviour and subcritical crack growth.
Together with several European research groups we prepare and characterize metalceramic
composites and metal-ceramic functionally graded materials
Materials under consideration are ZrO2, Al2O3/Cu and Al2O3/Al as well as various
piezoceramics.
3. Ferroelectric materials:
Two scientific questions are of interest for this group. Reliability of piezoceramics for
applications as actuator materials is under investigation. An increasing number of electrical
cycles leads to a progressive loss of obtainable strain and polarisation in these materials.
Therefore electrical fatigue as influenced by the type of electrical loading, uniaxial stress,
frequency and temperature are investigated. Recently, we developed a new method for
stress-assisted (electromechanical poling), which reduces the required poling field
considerably. Different new piezoceramics are being developed, especially new lead-free
compositions, but also high-temperature piezoceramics.
Materials under consideration are PZT, lead-free piezoceramics and high-temperature
piezoceramics.
- 15 -

Staff Members
Head
Prof. Dr. Jürgen Rödel
Research Associates Dr. Torsten Granzow
Dr. Olivier Guillon
Dr. Alain Brice Kounga Njiwa
Technical Personnel
Secretaries
PhD Students
Dr. Ludwig Weiler
Dr. Ruzhong Zuo
Dr. Nina Balke
Emil Aulbach Herbert Hebermehl
Roswita Geier
M. Sc. Ilona Westram
Dipl.-Ing. Julian Mircea
Dipl. Min. Ingo Kerkamm
M. Phys. Klaus Seifert
M. Sc. Jami Winzer
Dipl. Phys. Julia Glaum
Dipl.-Ing. Thorsten Leist
Diploma Students Lotta Gaab
Markus König
Silke Schaab
Martin Molberg
Bernd Meidel
Andrea Engert
Guest Scientists
Research Projects
Martin Frommherz
Gila Völzke
Dipl.-Phys. Thorsten Schlegel
Dipl.-Ing. Johanna Wallot
Dipl.-Ing. Daniel Meyer
Dipl.-Ing. J.-Baptiste Ollagnier
Dipl.-Ing. Silke Schaab
Dipl.-Ing. Jochen Langer
Dipl.-Ing. Markus König
Goran Pavlovic
Jochen Langer
Thorsten Leist
Joel Kamwa
Florian Straub
Prof. Dr. Sang Kezheng (University Xian)
Dr. Shan-Tao Zhang (University Nanjing)
Prof. Dr. David Green (Pennsylvania State University)
Zuzanna Pouiznik (IPPT Warschau)
Simonas Greicius (Universität Vilnius, Litauen)
Andrius Lektutis (Universität Vilnius, Litauen)
Julius Pozingis (Universität Vilnius, Litauen)
Jaemyung Chang (KAIST, Südkorea)
Enzo Chiarullo (Universität Mailand)
Crack growth in ferroelectrics driven by cyclic electric loading (DFG and NSFC, 2002-
2006)
Processing of textured ceramic actuators with high strain (SFB 595, 2003-2006)
Model experiments to describe the interaction between ferroelectric domains and
agglomerates (SFB 595 2003-2006)
- 16 -

Mesoscopic and macroscopic fatigue in doped ferroelectric ceramics (SFB 595), 2003-
2006
Development of anisotropy during sintering of LTCC materials (DFG, 2004-2006)
Sintering of TiO2 with additives (Merck, 2004-2007)
Knowledge-based multicomponent materials (EU, 6 th framework programme, 2004-2008)
Electrooptical properties of PLZT (DFG 2006-08)
High-temperature piezoceramics (DFG 2006-08)
Printed Electronics: Thin film ZnO (Merck 2006-09)
Developing a ceramic roadmap (DFG 2005-07)
Publications
Kounga Njiwa, A. B.; Fett, T.; Lupascu D.C.; Rödel, J.; Effect of Geometry and electrical
boundary conditions on R-curves for lead zirconate titanate; Eng. Fract. Mech., 73 (2006)
309.
Bordia R. K.; Zuo R.; Guillon O.; Salamone S.M.; Rödel J.; Anisotropic Constitutive Laws
for Sintering Bodies; Acta Materialia, 54 (2006) 111.
Lupascu D. C.; Genenko Y. A.; Balke N.; Aging in Ferroelectrics; J. Am. Ceram. Soc., 89
[1] (2006) 224.
Rao B. S.; Hemambar C.; Pathak A. V.; Pathel K. J.; Rödel J.; Jayram V.; Al/SiC Carriers
for Microwave Integrated Circuits by a New Technique of Pressureless Infiltration; IEEE
Transactions on Electronic Packaging Manufacturing, 29 [1] (2006) 58.
Kounga Njiwa A. B.; Aulbach E.; Rödel J.; Turner S. L.; Comyn T. P.; Bell A. J.;
Ferroelasticity and R-Curve Behavior in BiFeO3–PbTiO3; J. Am. Ceram. Soc., 89 [5]
(2006) 1761.
Zuo R.; Rödel J.; Chen R.; Li L.; Sintering and Electrical Properties of Lead-Free
Na0.5K0.5NbO3 Piezoelectric Ceramics; J. Am. Ceram. Soc., 89 [6] (2006) 2010.
Granzow T.; Kounga A. B.; Aulbach E.; Rödel J.; Electromechanical poling of
piezoelectrics; Appl. Phys. Lett., 88 (2006) 252907.
Kounga Njiwa A. B.; Aulbach E.; Rödel J.; Mechanical Properties of Dry-Pressed Powder
Compacts: Case Study on Alumina Nanoparticles; J. Am. Ceram. Soc., 89 [8] (2006) 2641.
Eichler J.; Hoffman M.; Eisele U.; Rödel J.; R-curve behaviour of 2Y-TZP with submicron
grain size; J. Eur. Ceram Soc., 26 (2006) 3575.
- 17 -

Zhou L.; Rixecker G.; Aldinger F.; Zuo R.; Zhao Z.; Electric Fatigue in Ferroelectric Lead
Zirconate Stannate Titanate Ceramics Prepared by Spark Plasma Sintering; J. Am.
Ceram. Soc., 89 [12] (2006) 3868.
Balke N.; Lupascu D. C.; Blair T.; Gruverman A.; Thickness profile through fatigued bulk
ceramic lead zirconate titanate; J. Appl. Phys.,100 (2006) 114117.
Ollagnier J.-B.; Guillon O.; Rödel J.; Viscosity of LTCC Determined by Discontinuous
Sinter-Forging; Int. J. Appl. Ceram. Technol., 3 [6] (2006) 437.
Granzow, T.; Suvaci E.; Kungl H.; Hoffmann J.; Deaging of heat-treated iron-doped lead
zirconate titanate ceramics; Appl. Phys. Lett., 89 (2006) 262908.
- 18 -

Electronic Material Properties
The department Electronic Materials introduces the aspect of electric functional materials
and their properties into the Institute of Materials Science. The associated research
concentrates on the characterization of various classes of materials suited for
implementation in information storage and organic electronics. Three major research
topics are presently addressed:
� Electronic and optoelectronic properties of organic semiconductors.
� Charge transport and polarization in organic dielectrics.
� Photo- and photostimulated luminescence in inorganic phosphors.
A worldwide interest exists in the use of organic semiconductors in electronic and
optoelectronic components, such as transistors and organic light emitting diodes, for novel
areas of application. So far, multicolor organic displays have been implemented in
commercially available cameras, car-radios, PDAs and mp3-players. Organic devices
reaching further into the future might be simple logic circuits, constituting the core of
communication electronics such as chip cards for radio frequency identification (RFID)
tags and maybe one day flexible electronic newspapers where the information is
continuously renewed via local area networks (LAN). In view of the mandatory
technological development, the activities of the group are concerned with the
characterization of organic material properties regarding the performance of organic
electronic and optoelectronic devices. The major aspect deals with the charge carrier
injection and transport taking place in organic field-effect-transistors and light emitting
diodes. In particular the impact of electronic properties of the insulator / semiconductor
interface on the performance of organic field-effect-transistors was subject of recent
investigations. This research is of great technological importance, since it opens the field
of complementary metal oxide semiconductor (CMOS) technology to organic
semiconductors. A further matter of research activities deals with the stability of organic
light emitting diodes. With the intention to enhance the device stability and performance,
the influence of the device operation on the device life-time in conjunction with material
and device specific properties is in the focus of interest. To conduct these demanding
tasks, various experimental techniques for device fabrication and characterization are
installed. Beside basic electric measurement setups, a laser spectroscopy setup, used for
time-of-flight as well as a life-time measurements, and a Kelvin-probe atomic force
microscope (AFM) to visualize the potential distribution of organic devices with nanometer
resolution are available.
In the field of polymer electrets present research comprises the characterization of surface
charge distribution, charge stability, and charge transport properties of fluoropolymers, as
well as their applications in acoustical transducers. Present investigations of charge
transport and polarization in organic dielectrics are directed towards the basic
understanding of polarization buildup and stabilization in PVDF and novel microporous
dielectrics, which are scientifically interesting as model ferroelectric polymers. The
available equipment includes poling devices, such as corona and high voltage setups, and
a thermally stimulated current setup to investigate the energetic trap structure in dielectrics
as well as the thermal charging and discharging under high electric fields.
The field of photo- and photostimulated luminescent (PSL) materials (phosphors) is
- 19 -

concerned with the synthesis and characterization of suited inorganic compounds. Such
materials are used as wavelength converters in fluorescent lamps and in scintillating and
information storing crystals. Present work is focused on x-ray detection materials, which
exhibit needle-like growth, needed for improved resolution in medical imaging. In particular
cesium halides-based storage phosphors and scintillators are under investigation. Further
research is concentrated on the low radiation hardness of CsBr:Eu 2+ . Radiation-induced
defects like color centers and precipitations are studied by means of spectroscopic
methods, electron microscopy and structural analysis.
In the field of storage phosphors also BaFBr:Eu 2+ used in commercial image plates is
investigated. On the one hand the mechanism of PSL-sensitization should be clarified. On
the other hand the production of foils and glass ceramics including BaFBr:Eu 2+ is in the
focus of the work.
Another topic is radiation scintillators, which convert x-ray energy immediately into visible
light, then detected by a CCD-array. For dynamical imaging in computer tomography (CT)
a fast decay of the emitted light is required. Therefore investigations are focused on the
mechanisms which influence the lifetime of the light emitting activator transitions.
Furthermore general challenges are the sensitization of such phosphors in respect to the
radiation energy, which can range from ultraviolet over hard γ-rays to thermal neutrons.
Staff Members
Head
Prof. Dr. Heinz von Seggern
Research Associate Dr. Kinga Horvath
Dr. Christian Melzer
Dr. Sergey V. Yampolskii
Technical Personnel
Secretary
PhD Students
Diploma Students
Gabriele Andreß
Sabine Hesse
Gerlinde Dietrich
Dipl.-Ing. Niels Benson
Dipl.-Ing. Arne Fleissner
Dipl.-Ing. Andrea Gassmann
Dipl.-Phys. Oliver Karg
Dipl.-Phys. Frederik Neumann
Dennis Braun
Andrea Gassmann
Urs Krämer
Tobias Lang
Humboldt-fellow Dr. Graham Appleby
Guest Scientist Prof. Dr. Sergei Fedosov
Prof. Dr. Robert Fleming
Dipl.-Phys. Xianguo Meng
- 20 -
Dr. Sergej Zhukov
Dr. Jörg Zimmermann
Bernd Stoll
Dipl.-Phys. Ulrich Niedermeier
Dipl.-Phys. Oliver Ottinger
Dipl.-Ing. Martin Schidleja
Dipl.-Ing. Christopher Siol
Dipl.-Ing. Oliver Weiß
Martin Schidleja
Hanna R. Schmid
Hans Schmidt

Research Projects
Fatigue of organic semiconductor components. (SFB (DFG), 2003-2006)
Phenomenological modelling of bipolar carrier transport in organic semiconducting devices
under special consideration of injection, transport and recombination phenomena. (SFB
(DFG), 2003-2006)
Investigation of fast scintillators with high efficiency for medical applications. (Siemens AG,
prolonged 2004-2006)
Piezoelectric sensor materials based on porous polymers. (BMWA-AiF 2005 – 2007)
Investigation of poled fluoropolymer membranes by means of surface corona treatment.
(Gore & Associates, 2003 – 2006)
Polymer Electronics: Investigation of functional instabilities of polymers and small molecule
based field effect transistors. (BMBF-DLR 2005 – 2008)
Investigation of the operation principle and optimisation of organic light emitting field effect
transistors. (DFG 2005 – 2007)
Self-organisation, orientation and electronic properties of organic thin films based on low
molecular weight, oligomeric and polymeric materials at the interface in field effect
transistors. (SPP (DFG) prolonged 2005 – 2007)
Charge carrier injection and transport in doped organic light emitting diodes. (BMBF-
OSRAM OS 2006 - 2009)
- 21 -

Publications
Fleissner, A.; Schmid, H.; Melzer, C.; Schmechel, R.; von Seggern, H.; Transition from
Non-Dispersive to Dispersive Hole Transport in a Small Molecule Organic Semiconductor
Controlled by Molecular Doping, MRS Proceedings 965E (2006) S14
Hesse, S.; Zimmermann, J.; von Seggern, H.; Ehrenberg, H.; Fuess, H.; Fasel, C.; Riedel,
R.; CsEuBr3: Crystal structure and its role in the photostimulation of CsBr : Eu 2+ , J. Appl.
Phys. 100 (2006) 083506
Neumann, F.; Genenko, Y. A.; Melzer, C.; von Seggern, H.; Self-consistent theory of
unipolar charge-carrier injection in metal/insulator/metal systems, J. Appl. Phys. 100
(2006) 084511
Benson, N.; Schidleja, M.; Melzer, C.; Schmechel, R.; von Seggern, H.; Complementary
organic field effect transistors by ultraviolet dielectric interface modification, Appl. Phys.
Lett. 89 (2006) 182105
Benson, N.; Ahles, M.; Schidleja, M.; Gassmann, A.; Mankel, E.; Mayer, T.; Melzer, C.;
Schmechel, R.; von Seggern, H.; Organic CMOS technology by interface treatment, Proc.
SPIE 6336 (2006) 63360S
Olivati, C. A.; Carvalho, A. J. F.; Balogh, D. T.; von Seggern, H.; Faria, R. M.; Effect of ion
concentration of ionomer in electron injection layer of polymer light-emitting devices, J.
Non-Cryst. Solids 352 (2006) 1686
Zhou, Y.; Yan, X.; Kroke, E.; Riedel, R.; Probst, D.; Thissen, A.; Hauser, R.; Ahles, M.; von
Seggern, H.; Deposition temperature effect on the structure and optical property of RF-
PACVD-derived hydrogenated SiCNO film, Mat.-wiss. u. Werkstofftech. 37 (2006) 173
Hu, Z.; von Seggern, H.; Breakdown-induced polarization buildup in porous fluoropolymer
sandwiches: a thermally stable piezoelectret, J. Appl. Phys. 99 (2006) 024102
Neumann, F.; Genenko, Y. A.; von Seggern, H.; The Einstein relation in systems with trapcontrolled
transport, J. Appl. Phys. 99 (2006) 013704
- 22 -

Surface Science
The surface science division of the institute of materials science uses advanced surface
science techniques to investigate surfaces and interfaces of materials and materials
combinations of technological use. For this purpose integrated UHV-systems have been
built up which combine different surface analytical tools (photoemission, electron
diffraction, ion scattering, scanning probe techniques) with the preparation of thin films
(thermal evaporation, close-spaced sublimation, magnetron sputtering, MOCVD) and
interfaces. The main research interest is directed to devices using polycrystalline
compound semiconductors and interfaces between dissimilar materials. The perspectives
of energy conversion (e.g. solar cells) or storage (intercalation batteries) devices are of
special interest. In addition, the fundamental processes involved in chemical and
electrochemical device engineering and oxide thin films for electronic applications are
investigated.
The main research areas are:
• Electrochemical Interfaces
The aim of this research activity is the better understanding of electrochemical
interfaces and contact formation. In addition, empirically derived (electro-) chemical
processing steps as the controlled modification and structuring of materials is
investigated and further optimized. In the center of our interest are
semiconductor/electrolyte contacts
• Intercalation Batteries
The aim of this research activity is the better understanding of electronic properties of
Li-intercalation batteries and of their degradation phenomena. Typically all solid state
batteries are prepared and investigated using sputtering and CVD techniques for
cathodes and solid electrolytes. In addition, the solid-electrolyte interface and
synthetic surface layers are investigated as well as composite systems for increasing
the capacity.
• Thin film solar cells
The aim of this research activity is the testing and development of novel materials
and materials combinations for photovoltaic applications. In addition, the interfaces in
microcrystalline thin film solar cells are to be characterized on a microscopic level to
understand and to further improve the empirically based optimisation of solar cells.
• Organic-inorganic interfaces and composites
In this research area we are aiming at the development of composites marterials for
(opto-)electronic applications. The decisive factors, which govern the electronic
properties of interfaces between organic and inorganic materials are studied.
• Oxide thin films for electronic applications
The aim of this research area is to understand electronic surface and interfaces
properties of oxides. We are mainly interested in transparent conducting oxide
electrodes for solar cells and organic LEDs but also in dielectric and ferroelectric
perovskites.
- 23 -

• Surface analysis
The UHV-surface science equipment and techniques using different and versatile
integrated preparation chambers is used for cooperative service investigations.
For the experiments we use integrated UHV-preparation and analysis-systems (UPS,
(M)XPS, LEISS, LEED), spectromicroscopy (PEEM) coupled with UHV-STM/AFM. We
further apply synchrotron radiation (SXPS, spectromicroscopy), scanning probe methods
(STM, AFM), and electrochemical measuring techniques. UHV-preparation chambers
dedicated for MBE, CVD, PVD and (electro)chemical treatment are available.
The member of the group are involved in basic courses of the department’s curriculum and
offer special courses on the physics, chemistry and engineering of semiconductor devices
and solar cells, on surface and interface science, and on thin film and surface technology.
Staff Members
Head
Prof. Dr. W. Jaegermann
Research Associates Dr. David Ensling
Dr. Ralf Hunger
Dr. Alexander Issanin
Technical Personnel
Secretary
PhD Students
Diploma Students
Dipl.-Ing. Erich Golusda
Dipl.-Ing. Gabi Haindl
Marga Lang
Dipl.-Ing. Yvonne Gassenbauer
Dipl.-Ing. Christoph Körber
Dipl.-Ing. Johannes Luschitz
Dipl.-Ing. Erik Mankel
Dipl.-Ing. Frank Säuberlich
Mario Böhme
Maxime Monnoyer
Bastian Siepchen
Guest Scientist Alireza Barati
Dr. Sivakumar Bhuvaneswari
Dr. Massimiliano Liberatore
Dr. Venkata Rao Gutlapalli
Krishnakumar Velappan
- 24 -
Dr. Andreas Klein
Dr. Thomas Mayer
Dr. Andreas Thißen
Kerstin Lakus-Wollny
Christina Spanheimer
Dipl.-Ing. Bastian Siepchen
Dipl.-Ing. Robert Schafranek
Dipl.-Ing. Konrad Schwanitz
Dipl.-Ing. Bettina Späth
Dipl.-Ing. Ulrich Weiler
Mark Trummlitz
André Wachau

Research Projects
Dedicated preparation-, transfer and spectrometer system for the analysis of materials
modifications and –synthesis at solid-liquid-interfaces with synchrotron radiation (BMBF,
2001-2007)
High performance CdTe thin film solar cells
(2003 – 2007)
Intercalnet
(EU, 2003 – 2006)
Boundary layers and thin films of ionic conductors: Electronic structure, electrochemical
potentials, defect formation and degradation mechanisms
(DFG – SFB, 2003 – 2006)
Function and fatigue of conducting electrodes in organic LEDs and piezoceramic actuators
(DFG – SFB, 2003 – 2006)
Tunable Integrated Components for Microwaves and Optics
Graduiertenkolleg 1037 (07/2004 – 12/2008)
Materials World Network: Interdisciplinary bulk/surface studies of transparent conducting
oxides
(2006 – 2009)
Hybrid structures of TsLiMPO4 phospho-olivines with C-nanofilaments for Li-ion-batteries:
preparation, properties and potential applications
(DFG – SPP1181, 2006 – 2008)
Chemical vapor deposition (PE-MOCVD) of cation-substituted transition metal oxide thin
films (Li(Co1-xNix)1-yMy02 (M=Mg, Al) for intercalation cathodes: structure, electronic
structure and electrochemical parameters
(DFG, 2005 – 2007)
Publications
U. Weiler, K. Schwanitz, C. Kelting, D. Schlettwein, D. Wöhrle, T. Mayer and W.
Jaegermann, Phthalocyanines Incorporated into Hot Wire-CVD Grown Silicon, Thin Solid
Films 511-512, 172 (2006)
T. Mayer, M. Lebedev, R. Hunger, W. Jaegermann, Synchrotron Photoemission Analysis
of Semiconductor/Electrolyte Interfaces by the Frozen-Electrolyte Approach: Interaction of
HCl in 2-Propanol with GaAs(100), J. Phys. Chem. B; 110, 2293-2301 (2006)
C. Kelting, U.Weiler, T.Mayer, W. Jaegermann, S. Makarov, D. Wöhrle, O. Abdallah, M.
Kunst, and D. Schlettwein, Sensitization of thin-film-silicon by a phthalocyanine as strong
organic absorber, Organic Electronics 7, 363–368, (2006)
- 25 -

T. Mayer, U. Weiler, E. Mankel and W. Jaegermann, Bulk sensitization of inorganic
semiconductors with organic guest molecules: zink-phthalozyanine embedded into µc-Si
and ZnSe host matrices , Proc. 4th World Conference on Photovoltaic Energy Conversion
T. Deniozou, N. Esser, T. Schulmeyer, R. Hunger, A (4x2) surface reconstruction of
CuInSe2(001) studied by low-energy electron diffraction and soft x-ray photoemission
spectroscopy, Applied Physics Letters 88(5) (2006), p. 052102-3.
R. Hunger, W. Jaegermann, A. Merson, Y. Shapira, C. Pettenkofer, J. Rappich, Electronic
structure of methoxy-, bromo-, and nitrobenzene grafted onto Si(111), Journal of Physical
Chemistry B 110(31); 15432-15441.
Y. Gassenbauer, R. Schafranek, A. Klein, S. Zafeiratos, M. Hävecker, A. Knop-Gericke, R.
Schlögl, Surface potential changes of semiconducting oxides monitored by high-pressure
photoelectron spectroscopy: Importance of electron concentration at the surface, Solid
State Ionics 177, 3123-3127 (2006).
S.P. Harvey, T.O. Mason, Y. Gassenbauer, R. Schafranek, A. Klein, Surface vs. Bulk
Electronic/Defect Structures of Transparent Conducting Oxides. Part I. Indium Oxide and
ITO, Journal of Physics D: Applied Physics 39, 3959-3968 (2006).
Y. Gassenbauer, R. Schafranek, A. Klein, S. Zafeiratos, M. Hävecker, A. Knop-Gericke, R.
Schlögl, Surface states, surface potentials and segregation at surfaces of tin-doped In2O3,
Physical Review B 73, 245312 (2006).
P. Erhart, K. Albe, A. Klein, First-principles study of intrinsic point defects in ZnO: Role of
band structure, volume relaxation, and finite-size effects, Physical Review B 73, 205203
(2006).
R. Schafranek, A. Klein, In-situ photoemission study of the contact formation of
(Ba,Sr)TiO3 with Cu and Au , Solid State Ionics 177, 1659-1664 (2006).
Y. Gassenbauer, A. Klein, Electronic and chemical properties of ITO surfaces and
ITO/ZnPc interfaces studied in-situ by photoelectron spectroscopy, Journal of Physical
Chemistry B 110, 4793-4801 (2006).
A. Sivasankar Reddy, P. Sreedhara Reddy, S. Uthanna, G. Venkata Rao, A. Klein, Effect
of substrate temperature on the physical properties of dc magnetron sputtered Cu2O films,
Physica Status Solidi (a) 203, 844-853 (2006).
A. Klein, T. Schulmeyer, Interfaces of Cu-chalcopyrites, in Wide gap chalcopyrites edited
by S. Siebentritt and U. Rau (Springer-Verlag, Heidelberg, 2006).
F. Rüggeberg, A. Klein, The In2O3/CdTe interface: A possible contact for thin film solar
cells?, Applied Physics A 82, 281-285 (2006).
Q.-H.Wu, A. Thissen, W. Jaegermann, M. Schuez, P.C. Schmidt, Resonant photoemission
spectroscopy study of electronic structure of V2O5, Chemical Physics Letters 430, 309-313
(2006).
- 26 -

Q.-H. Wu, A. Thissen, W. Jaegermann, Photoemission spectroscopy and electronic
structures of LiMn2O4, Chinese Physics Letters 23, 2202-2205 (2006).
F. Donsanti, K. Kostourou, F. Decker, N. Ibris, A.M. Salvi, M. Liberatore, A. Thissen, W.
Jaegermann, D. Lincot, Alkali ion intercalation in V2O5: preparation and laboratory
characterization of thin films produced by ALD, Surface and Interface Analysis 38, 815-818
(2006).
Y.P. Zhou, D. Probst, A. Thissen, E. Kroke, R. Riedel, R. Hauser, H. Hoche, E. Broszeit,
P. Kroll, H. Stafast, Hard silicon carbonitride films obtained by RF-plasma-enhanced
chemical vapour deposition using the single-source precursor
bis(trimethylsilyl)carbodiimide, Journal of the European Ceramic Society 26, 1325-1335
(2006).
Y. Zhou, X. Yan, E. Kroke, R. Riedel, D. Probst, A. Thissen, R. Hauser, M. Ahles, H. von
Seggern, Deposition temperature effect on the structure and optical property of RF-
PACVD-derived hydrogenated SiCNO film, Materialwissenschaft und Werkstofftechnik 37,
173-177 (2006).
- 27 -

Thin films
The Thin Film division works on advanced thin film deposition techniques of novel
materials. In the year 2006 we have introduced a new laser assisted deposition method at
TU Darmstadt, pulsed laser deposition (PLD). In collaboration with the Max-Planck-
Institute for Solid State Physics in Stuttgart, another frontier thin film deposition system has
been designed: a dedicated oxide Molecular Beam Epitaxy (MBE) system (oxide-MBE).
This system is to be one of a few systems worldwide offering comparable functionalities.
We expect that the introduction of two state-of-the-art thin film deposition techniques at TU
Darmstadt will advance the search for novel and enhanced oxide thin films.
The class of oxide ceramics, in particular with perovskite and derived structures,
comprises a stunning variety of new functional materials. Examples are high-temperature
superconductors, magnetic oxides for spintronics, high-k dielectrics, ferroelectrics,
and materials for thin film batteries. As a vision for future, new solid state matter can be
created by building hetero- and composite structures combining different oxide materials.
While present day electronic devices heavily rely on semiconducting materials, a future
way to create novel functional devices could be based on oxide electronics. Oxide
electronics and spintronics are part of the research and graduate education program
“Matronics” that has been applied for within the Excellence Initiative by the the German
federal and state governments to promote science and research at German universities.
Matronics is coordinated by Lambert Alff (Thin Film division) and Heinz von Seggern
(Electronic Materials division) and has been positively evaluated in the first round of the
Excellency Initiative.
The characterization tools located in the Thin Film division include x-ray diffraction (XRD),
x-ray photoemission spectroscopy (XPS), high-resolution scanning electron microscopy
(HREM) with light element sensitive EDX, and SQUID magnetometry. A new 16 Tesla
magnet cryostat allowing measurements down to liquid helium temperature has been
installed. Another magnet cryostat lowering the available temperature range to below 300
mK is currently being installed. The group is also using external large scale facilities as
synchrotron radiation (ESRF, Grenoble) and neutron reactors (ILL, Grenoble / HMI, Berlin /
FRM II, Garching) for advanced sample characterization. There is an ongoing cooperation
with GSI (Darmstadt) and with the Institute for Nuclear Physics at the Goethe-University
(Frankfurt) in the field of ion beam techniques (e.g. RBS, NRA, IBM) and nuclear probe
methods (positron annihilation and Mössbauer spectroscopy), in particular with the
direction of defect and interface structure investigations.
Close cooperation exists in particular with the Max-Planck-Institute for Solid State
Research in Stuttgart and with the Japanese company NTT in Atsugi near Tokio. As a new
group member, Dr. Komissinskiy can be welcomed, who has spent several successful
years at the renowned Chalmers University of Technology in Göteborg, Sweden.
In teaching the group is offering courses and lab exercises in basic materials science as
part of the department’s main curriculum. New special courses for advanced students on
Magnetism and Magnetic Materials, Spintronics as well as Advanced Materials have been
introduced. The group is also giving a practical introduction in high-resolution scanning
electron microscopy and ion beam techniques for students and researchers in the field.
In 2006 Lambert Alff has accepted the position of Dean of Studies for Materials Science.
- 28 -

Staff Members
Head / Secretary Prof. Dr. Lambert Alff Marion Bracke
Research Dr. Adam G. Balogh Dr. Philipp Komissinskiy
Associates Dr. Jose Kurian
Technical Personnel Jürgen Schreeck
PhD Students Matthias Hawraneck Yoshiharu Krockenberger
Andreas Winkler
Diploma Students Ceena Joseph Narendirakumar Narayanan
Guest Scientists Dr. Sergej Duvanov, Institute for Applied Physics, Academy of
Sciences, Ukraine
Research Projects
Symmetry of the order parameter and pseudogap behavior in electron doped hightemperature
superconductors, within Research Unit 538 (DFG, 2004-2006)
Superconductivity in water intercalated NaxCoO2 thin films (TU Darmstadt, TU
Braunschweig, and Max-Planck-Institute for Solid State Research, Stuttgart (DFG, 2006-
2010)
Fabrication of electron-doped high-temperature superconductors (TUD & NTT, Japan,
since 1999)
Investigation of defect structure and diffusion in ferroelectric materials, Project B2 within a
Collaborative Research Center (SFB 595, 2003-2010)
Atomic transport and transient processes at nanostructured metal/ceramic and
ceramic/ceramic systems, BMBF, UKR 05/003 (2006-2008)
Study of defect structure of semiconductors and intermetallic phases (TU Darmstadt & TU
Graz, since 1996)
Publications
Alff, L.; Die spinnen, die Oxide: Neue Materialien für die Spintronik; in: Thema Forschung:
Intelligente Materialien, TU Darmstadt 2/2006.
Bejarano, G.; Caicedo, J.M.; Baca, E.; Prieto, P.; Balogh, A.G.; Enders, S.; Deposition of
B4C/BCN/c-BN multilayered thin films by r.f. magnetron sputtering; Thin Solid Films 494
(2006) 53-57.
- 29 -

Berky, W.; Gottschalk, S.; Elliman, R.G.; Balogh, A.G.; Orientation dependent ion beam
mixing of Ta/Si interfaces; Nucl. Instr. and Meth. B 249 (2006) 200-203.
Geprägs, S.; Majewski, P.; Gross, R.; Ritter, C.; Alff, L.; Electron doping in the double
perovskite LaxA2-xCrWO6 with A = Sr, Ca, and Ba; J. Appl. Phys. 99 (2006) 08J102.
Karim, S.; Toimil-Molares, M.E.; Balogh, A.G.; Ensinger, W.; Cornelius, T.W.; Khan, E.U.;
Neumann, R.; Morphological evolution of Au nanowires controlled by Rayleigh instability;
Nanotechnology 17 (2006) 5954-5959
Kornev, V.K.; Karminskaya, T.Y.; Kislinskii, Yu.V.; Komissinki, P.V.; Constantinian, K.Y.;
Ovsyannikov, G.A.; Dynamics of underdamped Josephson junctions with nonsinusoidal
current-phase relation; Physica C 435 (2006) 27–30.
Krockenberger, Y.; Fritsch, I.; Cristiani, G.; Habermeier, H.-U.; Yu, L.; Bernhard, C.;
Keimer, B.; Alff, L.; Superconductivity in epitaxial thin films of NaxCoO2* yD2O; Appl. Phys.
Lett. 88 (2006) 162501.
Ovsyannikov, G.A.; Borisenko, I.V.; Komissinskii, P.V.; Kislinskii, Yu.V.; Zaitsev, A.V.;
Anomalous proximity effect in superconducting oxide structures with an antiferromagnetic
layer, JETP Lett. 84 (2006) 262-266.
Ovsyannikov, G.A.; Constantinian, K.Y.; Kislinskii, Yu.V.; Komissinskii, P.V.; Borisenko,
I.V.; Karminskaya, T.Yu.; Kornev, V.K.; Microwave dynamics of Josephson structures with
nontrivial current-phase relation; J. Comm. Technology and Electronics 51 (2006) 1078-
1086.
- 30 -

Dispersive Solids
The research of the Dispersive Solids group is based on the development of strategies for
producing novel inorganic, oxidic, and non-oxidic materials. The main focus is the
synthesis of ceramics with properties which exceed the present state of the art.
Synthesis methods like the sol-gel-technology, polymer pyrolysis and chemical vapour
deposition (CVD) as well as high pressure/high temperature synthesis in diamond and
multi anvil cells are used and continuously further developed. Moreover molecular,
oligomeric, and polymeric ceramic precursors as well as inorganic materials derived
therefrom are synthesized and characterized. Further emphasis is put on the
transformation of the precursors into ceramic components (for example layers, fibers, bulk
materials, composites, membranes) and the characterization of their chemical and
physical materials properties. The aim of our research activities is to correlate those
properties with the composition and structure of the molecular precursors.
The present projects include the following four main topics: materials synthesis, properties,
modeling, and processing & applications.
Staff Members
Head
Prof. Dr. Dr. h. c. Ralf Riedel
Research Associates Dr. Hans-Gerhard Bremes
Dr. Aleksander Gurlo
Dr. Ralf Hauser
Dr.-Ing. Elisabeta Horvath-
Bordon
Technical Personnel
Secretaries
PhD Students
Dipl.-Ing. Claudia Fasel
Su-Chen Chang Karen Böhling
Dipl.-Ing. Ricardo Chavez
Dipl.-Ing. Susanne Deuchert
M.Tech. Dmytro Dzivenko
Dipl.-Min. Michael Eberhardt
Dipl.-Ing. Alexander
Klonczynski
- 31 -
Dr. Emanuel Ionescu
Dr. Isabel Kinski
Dr. Sandra Martinez-Crespiera
Dr. Gabriela Mera
Dr. Liviu Toma
Dipl.-Chem. Verena Liebau-
Kunzmann
Dipl.-Ing. Ilaria Menapace
Dipl.-Ing. Bernard Rodrigue
Ngoumeni Yappi
Dipl.-Ing. Vassilios Siozios

Guest Scientists
Research Projects
Prof. Dr. Corneliu Balan, Politehnica, Univ. of Bucharest,
Romania
Dr. Matilda Zemanova, Faculty of Chem. Technology, Slovak
University of Technology, Slovakia
Sepideh Kamrani, Sharif University of Technology, Teheran,
Iran
Lisa Biasetto, Università di Padova, Italy
Prof. Dr. Yali Li, Tianjin University, China
Novel functional ceramics with substitution of anions in oxide systems, (DFG, SFB 595,
project A4, since Jan. 2003)
High pressure synthesis of novel nitrides of model M3-xAxN4 (M, A = V, Nb, Ta, Ti, Zr, Hf,
Pb; 0

Publications
Zhou, Y.; Probst, D.; Thissen, A.; Kroke, E.; Riedel, R.; Hauser, R.; Hoche, H.; Broszeit,
E.; Kroll, P.; Stafast, H.; Hard Silicon Carbonitride Films Obtained by RF-Plasma
Enhanced Chemical Vapour Deposition Using the Single Source Precursor
Bis(trimethylsilyl)-carbodiimide, J. Europ. Ceram. Soc. 26 (2006) 1325-1335.
Liebau-Kunzmann, V.; Fasel, C.; Kolb, R.; Riedel, R.; Lithium Containing Silazanes as
Precursors for SiCN:Li Ceramics – A Potential Material for Electrochemical Applications, J.
Europ. Ceram. Soc. 26 (2006) 3897-3901.
Kolb, R.; Fasel, C.; Liebau-Kunzmann, V.; Riedel, R.; SiCN/C-Ceramic Composite as
Anode Material for Lithium Ion Batteries, J. Europ. Ceram. Soc. 26 (2006) 3903-3908.
Zhou, Y.; Yan, X.; Kroke, E.; Riedel, R.; Probst, D.; Thissen, A.; Hauser, R.; Ahles, M.; von
Seggern, H.; Deposition Temperature Effect on the Structure and Optical Property of RF-
PACVD-Derived Hydrogenated SiCNO Film, Materialwissenschaft und Werkstofftechnik
37 (2006) 173-177.
Zerr, A.; Riedel, R.; Sekine, T.; Lowther, J.E.; Ching, W.-Y.; Tanaka, I.; Recent Advances
in New Hard High-Pressure Nitrides, Adv. Mat. 18 (2006) 2933.
Hauser, R.; Nahar-Borchard, S.; Riedel, R.; Ikuhara, Y.H.; Iwamoto, Y.; Polymer-Derived
SiBCN Ceramic and their Potential Application for High Temperature Membranes”, J.
Ceram. Soc. Jpn. 114 (2006) 567-570.
Völger, K.W.; Hauser, R.; Kroke, E.; Riedel, R.; Ikuhara, Y.H.; Iwamoto, Y.; Synthesis and
Characterization of Novel Non-Oxide Sol-Gel Derived Mesoporous Amorphous Si-C-N
Membranes, J. Ceram. Soc. Jpn. 114 (2006) 524-528.
Balan, C.; Riedel, R.; Rheological Investigations of a Polymeric Precursor for Ceramic
Materials: Experiments and Theoretical Modelling, J. Optoelec. Adv. Mat. 8 (2006) 561-
567.
Riedel, R.; Mera, G.; Hauser, R.; Klonczynski, A.; Silicon-Based Polymer-Derived
Ceramics: Synthesis, Properties and Applications --- A Review, J. Ceram. Soc. Jpn. 114
(2006) 425-444.
Ischenko, V.; Harshe, R.; Riedel, R.; Woltersdorf, J.; Cross-Linking of Functionalised
Siloxanes with Alumatrane: Reaction Mechanisms and Kinetics, J. Organomet. Chem. 691
(2006) 4086-4091.
Dzivenko, D.A.; Zerr, A.; Boehler, R.; Riedel, R.; Equation of State of Cubic Hafnium(IV)
Nitride Having Th3P4-Type Structure, Solid State Comm. 139 (2006) 255-258.
Horvath-Bordon, E.; Riedel, R.; Zerr, A.; McMillan, P.F.; Auffermann, G.; Prots, Y.;
Bronger, W.; Kniep, R.; Kroll, P.; High-Pressure Chemistry of Nitride-Based Materials,
Chem. Soc. Rev. 35 (2006) 987-1014.
- 33 -

Hesse, S.; Zimmermann, J.; von Seggern, H.; Ehrenberg, H.; Fueß, H.; Fasel, C.; Riedel,
R.; CsEuBr3: Crystal Structure and Its Role in the Photostimulation of CsBr:Eu 2+ , J. Appl.
Phys. 100 (2006) 083506.
Enz, T.; Winterer, M.; Stahl, B.; Bhattacharya, S.; Miehe, G.; Foster, K.; Fasel, C.; Hahn,
H., Structure and magnetic properties of iron nanoparticles stabilized in carbon, J. Appl.
Phys. 99 (2006) 044306.
Riedel, R.; Wakai, F.; Special Issue dedicated to Professor Günter Petzow on the
Occasion of his 80th Birthday: Modern Trends in Advanced Ceramics, J. Ceram. Soc. Jpn.
114 (2006) 1335.
Graf, M.; Gurlo, A.; Barsan, N.; Weimar, U.; Hierlemann, A.; Microfabricated gas sensor
systems with nanocrystalline metal-oxide sensitive films, J. Nanoparticle Research 8
(2006) 823.
Gurlo, A.; Barsan, N.; Weimar, U.; Gas sensors based on semiconducting metal oxides, in
Metal Oxides: Chemistry and Applications, Ed. J.L.G.Fierro, CRC Press, Boca Raton,
2006, pp. 683-738.
Gurlo, A.; Interplay between O2 and SnO2: oxygen ionosorption and spectroscopic
evidence of adsorbed oxygen (Minireview), ChemPhysChem 7 (2006) 2041.
Sahm, T.; Gurlo, A.; Barsan, N.; Weimar, U.; Properties of indium oxide semiconducting
sensors deposited by different techniques, Particulate Science and Technology 24 (2006)
441.
Mädler, L.; Sahm, T.; Gurlo, A.; Grunwaldt, J.D.; Barsan, N.; Weimar, U.; Pratsinis, S.E.;
Sensing low concentrations of CO using flame-spray-made Pt/SnO2 nanoparticles, J.
Nanoparticle Research, 8 (2006) 783.
Sahm, T.; Gurlo, A.; Barsan, N.; Weimar, U.; Basics of oxygen and SnO2 interaction: work
function change and conductivity measurements, Sens. Actuators B 118 (2006) 78.
Mädler, L.; Roessler, A.; Pratsinis, S.E.; Sahm, T.; Gurlo, A.; Barsan, N.; Weimar, U.;
Direct formation of highly porous gas-sensing films by in-situ thermophoretic deposition of
flame-made Pt/SnO2 nanoparticles, Sens. Actuators B 114 (2006) 283.
Polleux, J., Gurlo, A.; Barsan, N.; Weimar, U.; Antonietti, M.; Niederberger, M.; Templatefree
synthesis and assembly of single-crystalline tungsten oxide nanowires and their gassensing
properties, Angew. Chem. Int. Ed., 45 (2006) 261.
- 34 -

Patents
Heinrich, J.G.; Günster, J.; Rastätter, S.; Riedel, R.; Verfahren und Vorrichtung zur
Herstellung von dreidimensionalen keramischen Strukturen, German Patent, Patent-No.
102 00 313, 27.04.2006.
Awards
Dr. Horvath-Bordon, Elisabeta; Honorary Research Fellow of the Department of
Chemistry, University College London, 1 Dec. 2006 – 1 Dec. 2009.
Prof. Dr. Riedel, Ralf; Honorary Doctorate (Dr. h. c.),12. Sep. 2006, Slovak Academy of
Sciences, Bratislava, Slovakia.
- 35 -

Structure Research
The research in the fields of heterogeneous catalysis, battery materials and magnetic
properties of oxides and alloys continued sucessfully during the last year. The division was
also very actively involved in the Center of Excellence on Fatigue.
The neutron powder diffractometer SPODI had its first year of full operation and fulfilled all
expectations as the instrument which attracted most proposals at FRM II. The beam-line
responsibles are Markus Hölzel and Anatoliy Senyshyn. The synchrotron powder beamline
B2 at HASYLAB is functioning in the frame-work of a Virtual Institute of the Helmholtz
society. The scientists at DORIS in Hamburg were Carsten Bähtz and Dmytro Trots.
Carsten Bähtz discontinued his contract with the Virtual Institute at the end of 2006 to take
a position at FZ Rossendorf. Hermann Pauly who continuously worked in the laboratory
after his retirement more or less stopped his successful research on Zintl-phases. Special
thanks are due to Helmut Ehrenberg who accepted an offer from Institut für Festkörper-
and Werkstoffforschung Dresden and left the institute on Sept. 30 after many years of
successful work in the group of structure research. Prof. Fuess officially retired at the end
of the summer semester but will continue in the frame of a contract with TU Darmstadt for
the next 3 years. He has been appointed as a rapporteur for the cooperative evolution of
five Max-Plack-Institutes and as chairman of the Comission for Joint Research at Large
Scale Facilities (Verbundforschung Erforschung kondensierter Materie an Großgeräten) of
the BMBF. He is a member of the Fachkollegium Kristallographie of DFG and numerous
evaluation commitees of DFG, CNRS, CSIC, ESF or of the European Union. He was
awarded a Humboldt-Research-Prize of the Foundation for Polish Science.
Staff Members
Head
Prof. Dr.-Ing. Dr. h.c. Hartmut Fueß
Research Associates Dr. Natalia Bramnik
Dr. Joachim Brötz
Dr. Helmut Ehrenberg
Dr. Achim Hohl
Dr. Markus Hölzel
Technical Personnel
Secretary
PhD Students
Dipl.-Ing. Heinz Mohren
Jean-Christophe Jaud
Maria Holzmann
Dipl.-Phys. Mouner Abdalslam
Dipl.-Phys. Jens Engel
Dipl.-Chem. Rachid Essehli
Dipl.-Chem. Lars Giebeler
Dipl.-Ing. Toni André Groß
Dipl.-Phys. Aleksandra Gruzdeva
Dipl.-Ing. Hanna Hahn
- 36 -
Dr. Daria Mikhailova
Dr. Isabel Kinski
Dr. Daria Mikhailova
Dr. Anatoliy Senyshyn
Dr. Hans Weitzel
Ingrid Svoboda
Dipl.-Ing. Kristian Nikolowski
Dipl.-Ing. Navid Qureshi
Dipl.-Ing. Frieder Scheiba
Dipl.-Ing Roland Schierholz
Dipl.-Ing Christian Schmitt
Dipl.-Ing. Ljubomira Schmitt
Dipl.-Min. Kristin Schönau

Diploma Student
Dipl.-Phys. Nyam-Ochir Lkhanaajav
Dipl.-Ing Thomas Locherer
Dipl.-Ing. Florian Maurer
Dipl.-Ing. Marian Mazurek
Manuel Hinterstein
Dipl. Ing. Dominic Stürmer
Dipl.-Ing. Björn Schwarz
Dipl.-Ing. Dmytro Trots
Dipl.-Ing. Emanuel Vollmar
Jens Kling
Guest Scientists Dr. Larisa Balsanova, Ulan Ude, Russia
Dr. Miroslav Boča, Academy of Sciences, Bratislava, Slovakia
Prof. Dr. Roman Boča, Technical University Bratislava, Slovakia
Prof. Dr. Abdelwahab Cheikhrouhou, University of Sfax, Tunisia
Dr. Rim Yong Chol, Academy of Sciences, Pyongyang,
Peoples Republic of Korea
Dr. Lubor Dlháň, Technical University Bratislava, Slovakia
Dr. Grygoriy Dmytriv, Ivan-Franko-University Lviv, Ukraina
Dr. Eno Ebenso, University of Calabar, Nigeria
Prof. Dr. Thimme Gowda, University of Mangalore, India
Dipl.-Ing. Radoslava Ivanikova, Technical University Bratislava, Slovakia
Dr. Radovan Herchel, Technical University Bratislava, Slovakia
Dr. Jozef Kožišek, Technical University Bratislava, Slovakia
Dr. Mohamed Loukil, University of Sfax, Tunisia
Dr. Anna Mašlejová, Technical University Bratislava, Slovakia
Dr. Anouar Njeh, University of Sfax, Tunisia
Dr. Blažena Papánková, Technical University Bratislava, Slovakia
Prof. Dr. Volodymyr Pavlyuk, Ivan-Franko-University Lviv, Ukraina
Dipl.-Ing. Jurij Pelikan, Technical University Bratislava, Slovakia
Dipl.-Ing. Lucia Perasinová, Technical University Bratislava, Slovakia
Dr. Nizar Rammeh, University of Sfax, Tunisia
Prof. Ismail Saadoune, University of Marakesh, Marocco
Prof. Dr. Deleg Sangaa, Nat. University, Ulaan Bator, Mongolia
Dr. Andre Skomorokhov, Institute for Physics, Obninsk, Russia
Dr. Jang Jong Su, Academy of Sciences, Pyongyang,
Peoples Republic of Korea
- 37 -

Research Projects
Functional Advanced Materials and Engineering. Hybrides and Ceramics (FAME Network
of Excellence, 6 th Framework Programm EU, 2005-2008).
Development of in situ characterization techniques for polycrystalline materials using highenergy
synchrotron radiation (Virtual Institute, Impuls- und Vernetzungsfond of the
Helmholtz-Society, 2004-2007).
Design, realisation and operation of the new neutron structure powder diffractometer
(SPODI at the FRM-II, TU München in Garching, BMBF, 1998-2007).
Investigation of superionic conducting properties in the copper silver selenium system
(BMBF, 2004-2007).
Investigation on radiation induced modifications in NbTi superconducting materials
(cooperation with GSI, Darmstadt, 2004-2007).
Controlled deposition and structural investigations of metallic nanowires for field emission
applications (cooperation with GSI, Darmstadt, 2004-2006).
Synthesis and properties of new (oxid)nitrid-ceramics: spinell nitride and sialone (DFG,
2003-2007).
Structural phase transitions and physical properties of Zintl-phases with NaTl-type
structure (B32) at ambient condition (DFG, 2003-2006).
Magnetic phase diagram and correlations between structural and magnetic properties in
Cu(MoxW1-x)O4 (DFG, 2003-2006).
Preparation of new orthomolybdates of alkaline and 3d-transition metals and
characterization of magnetic, ion conducting and catalytic properties (DFG, 2004-2007).
Characterization of the three-phase boundary in differently synthesized membraneelectrode
assemblies (DFG, 2004-2007).
High pressure synthesis and magnetism of orthorhenates (DFG, 2005-2007).
Electron and magnetization density in the transition metal oxide Co3V2O8 (DFG, 2005-
2007).
The electron structure of TiO2 and VO2: A Joined Electron-Density Study of two Materials
in Position, Momentum and Phase Space (DFG, 2005-2007).
Ionic Fluids (Humboldt cooperation with Prof. Dr. V. Balevicius, Vilnius University,
Lithuania, 2003-2006).
- 38 -

Ternary phase diagrams containing Zintl-phases of the NaTl-type structure (B32)
(Scientific and technological cooperation (WTZ) with Prof. Dr. V. Pavlyuk, Ivan-Franko-
University Lviv, Ukraina, 2004-2006).
The magnetic interactions and magnetostructural correlations in R’xR1-xMn2Ge2,
RMn2-xTxGe2 and R’xR1-xMn6Ge6 (R’, R = La, Ce, Pr, Nd, Nd, Cd, Tb, Dy, Gd, Ho, Er, Y
and T = Fe, Cr, Co, Cu) intermetallic compounds (Scientific and technological cooperation
(WTZ) with Prof. Dr. A. Elmali, University of Ankara, Turkey, 2004-2006).
DAAD exchange program with Slovakia (2006-2007).
Structural investigations into the electric fatigue in PZT (DFG-SFB, 2003-2006)
In-situ investigations of the degradation of intercalation batteries und their modelling (DFG-
SFB, 2003-2006)
Struktur und Wirkungsmechanismus der katalytisch aktiven Phasen (m) in V/W und Mo/W-
Mischoxid-Katalysatoren bei der Partialoxidation von einfachen Aldehyden (Acrolein zu
Acrylsäure)
(DFG 2006-2008)
Publications
Atakol, O.; Boča, R.; Ercan, I.; Ercan, F.; Fuess, H.; Haase, W.; Herchel, R.; Magnetic
properties of trinuclear Ni-M-Ni complexes, M = Mn, Co and Ni; Chem. Phys. Lett. 423,
(2006) 192-196
Benker, N.; Roth, C.; Mazurek, M.; Fuess, H.; Synthesis and characterization of ternary
Pt/Ru/Mo catalysts for the anode of the PEM fuel cell; J. New Mat. Electrochem. Syst. 9,
(2006) 121-126
Buhrmester, C.; Miehe, G.; Ehrenberg, H., Fuess, H.; 1-chloro-2,2-dimethylpropane:
Thermal analysis, powder diffraction and spectroscopic investigation of the solid phases;
Cryst. Res. Techn., 41, (2006) 48-54
Buhrmester, C.; Miehe, G.; Ehrenberg, H., Fuess, H., Thermal analysis, powder diffraction
and spectroscopic investigation of the solid phases of 1-chloro-2,2-dimethylpropane, Cryst.
Res. Technol. 41 (2006) 48-54.
Cakir, O.; Dincer, I.; Elmali, A.; Elerman, Y.; Ehrenberg, H., Fuess, H., Magnetic phase
transitions in the Gd1-xTmxMn6Sn6 compounds, J. Alloys Compd. 416(2006) 31-34.
Cao, L.; Scheiba, F.; Roth, C.; Schweiger, F.; Cremers, C.; Stimming, U.; Fuess, H., Chen,
L.; Zhu, W.; Qui, X.; Novel nanocomposite Pt/RuO2 . xH2O/carbon nanotube catalysts for
direct methanol fuel cells; Angew. Chem. Int. Ed. 45, (2006) 5315-5319
Dincer, I. ;Elerman, Y.; Elmali, A.;Ehrenberg, H.; Fuess, H., Baehtz, C.; Magneto-structural
correlations in Pr0.15Gd0.85Mn2Ge2; Sol. State Comm., 140, (2006) 245-247
- 39 -

Dincer, I.; Elerman, Y.; Elmali, A; Ehrenberg, H.; Fuess, H.; Baehtz, C.; Magneto-structural
correlations in Pr0.15Gd0.85Mn2Ge2, Solid State Communications 140(2006) 245-247.
Dincer, I. ; Elmali, A.; Elerman, Y.; H Ehrenberg, H.; Fuess, H., G. André; Neutron
diffraction study on PrMn2-xFexGe2 and general magnetic phase diagram for
RMn2-xFexGe2 (R=La-Sm); J. All. Comp., 416, (2006) 22-30
Ehrenberg, H., Laubach, S.; Schmidt, P. C.; McSweeney, R. ; Knapp, M.; Mishra, K. C.;
Investigation of crystal structure and associated electronic structure ofSr6BP5O20,J.Solid
State Chem. 179 (2006) 968-973.
Ehrenberg, H., Muessig, E.; Bramnik, K. G.; Kampe, P.; Hansen, T.; Preparation and
properties of sodium iron orthooxomolybdates, NaxFey (MoO4)z , Solid State Sciences 8
(2006) 813-820.
Ehrenberg, H.; Schwarz, B.; Weitzel, H.; Magneticphasediagrams of MnMoO4,J.Magn.
Magn. Mater. 305 (2006) 57-62.
Essehli, R.; El Bali, B.; Lachkar, M.; Svoboda, I.; Fuess, H.;
Bis(ethylenediammonium)diaquabis[hydrogendiphosphato(3-)]nickelate(II):structure and
vibrational spectroscoy; Acta Cryst E 62, (2006) m538-m541
Giebeler, L.; Kampe, P.; Wirth, A.; Adams, A.H.; Kunert, J.; Fuess, H., Vogel, H.; Structural
changes of vanadium-molybdenum-tungsten mixed oxide catalysts during the selective
oxidation of acrolein to acrylic acid; J. Mol. Catal. A: Chemical 259, (2006) 309-318
Gowda, B.T.; Kožišek, J.; Fuess, H.; Structural Studies on N-(2,4,6-Trimethylphenyl)methyl/chloro-acetamides,
2,4,6-(CH3)3C6H2NH-CO-CH3-yXy (X= CH3 or Cl and y = 0, 1, 2);
Z. Naturforsch. 61a, (2006) 588-594
Gowda, B.T.; Paulus, H.; Kožišek, J.; Tokarcik, M.; Fuess, H.; Effect of substitution on the
molecular geometry of N-(2/L3/4-substituted-phenyl)-2,2-dichloroacetamides, 2/3/4-
XC6H4NHCO.CHCl2 (X-CH3 or Cl); Z. Naturforsch., 61a, (2006) 675-682
Hartung, J.; Bergsträßer, U.; Greb, M.; Svoboda, I.; H. Fuess; cis-5-Bromo-2,2,6-trimethyltrans-6-phenyltetrahydropyran-3-carboxylic
acid; Acta Cryst E 62, (2006) o1920-o1922
Hartung, J.; Schwarz, M.; Paulus, E.F.; Svoboda, I.; Fuess, H.; 4-(4-Chlorophenyl)-3-(4phenylpent-4-enyloxy)-1,3,-thiazole-2(3H)-thione;
Acta Cryst. C62, (2006) o386-o388
Hartung, J.; Greb, M.; Svoboda, I.; Fuess, H.; (C)-(2,4-Di-tert-butyl-6-{[2S)-3,3-dimethyl-1oxido-2-butyl]iminomethyl}phenolato)ethanol-cis-dioxomolybdenum(VI)
at 100K; Acta
Cryst E 62, (2006) m275-m277
Hartung, J.; Greb, M.; Svoboda, I.; Fuess, H.; Methyl 5-cis-bromo-2,2,6-trimethyl-6-transphenyltetrahydropyran-3-carboxylate;
Acta Cryst, E62, (2006) o4975-o4976
Hartung, J.; Greb, M.; Svoboda, I.; Fuess, H.; 5-cis-Bromo-2,2,6,6tetramethyltetrahydropyran-3-carboxylic
acid; Acta Cryst E 62, (2006) o1918-o1919
- 40 -

Hartung, J.; Kopf, T.; Svoboda, I.; Fuess, H.; Trimethylammonium bromide at 100K; Acta
Cryst E62, (2006) o570-o572
Hartung, J.; Svoboda, I.; Fuess, H.; 1-(1-Adamantyloxy)pyridin-2(1H)-one; Acta Cryst E62,
(2006) o579-o581
Hesse, S.; Zimmermann, J.; von Seggern, H.; Ehrenberg, H.; Fuess, H.; Fasel, C.; Riedel,
R.; CsEuBr3: Crystal structure and its role in the photostimulation process of CsBr:Eu2+;
J. Appl. Phys. 100 (2006) 083506.
Ishihara, H. ; Horiuchi, K.;Svoboda, I.; Fuess, H.; Gesing, T.M.; Buhl, J.-Ch.; Terao, H.;
Crystal Structures of Piperazinium Tetrahalogenometallates (II) [C4H12N2]MX4(M=Zn, Hg;
X=Br,I); Z. Naturforsch. 61b, (2006) 69-72
Ivanda, M.; Hohl, A.; Montagna, M.; Mariotto, G.; Ferrari, M.; Crnjak Orel, Z.; Turković, A.;
Furić, K.; Raman scattering of acoustical modes of silicon nanoparticles embedded in
silica matrix; J. Raman Spectrosc. 37, (2006) 161-165
Ivaniková, R.; Boča, R.; Dlhán, L.; Fuess, H., Mašlejová, A.; Mrázová, V.; Svoboda, I.;
Titiš, J.; Heteroleptic nickel(II) complexes formed from N-donor bases, carboxylic acids
and water: Magnetostructural correlations; Polyhedron 25, (2006) 3261-3268
Ivaniková, R.; Svoboda, I; Fuess, H.; Mašlejová, A.; Trans-dichloro(1,4,8,11tetraazacyclotetradecane)cobalt(III)
chloride; Acta Cryst E62, (2006) m1553-m1554
Ivaniková, R.; Svoboda, I.; Mašlejová, A.; Papánková, B.; Fuess, H.; Bis(2,2’-bipyridineκ
2 N,N’)(nitrato- κ 2 O,O’)cobalt(II) iodide tetraydrate; Acta Cryst, E62, (2006) m3024-m3025
Karim, S.; Toimil-Molares, M.E.; Maurer, F.; Miehe, G.; Ensinger, W.; Liu, J.; Cornelius,
T.W.; Neumann, R.; Synthesis of gold nanowires with controlled crystallographic
characteristics; Appl. Phys. A., 84, (2006) 403-407
Maurer, F.; Dangwal, A.; Lysenkov, D.; Müller, G.; Toimil-Molares, M. E.; Trautmann, C.;
Brötz, J.; Fuess, H.; Field emission of copper nanowires grown in polymer ion-track
membranes; Nucl. Instr. Meth. Phys. Res. B245, (2006) 337-341
Mazurek, M.; Benker, N.; Roth, C.; Buhrmester, T.; Fuess, H.; Electrochemical impedance
and X-ray absorption spectroscopy (EXAFS) as in-situ methods to study the PEMFC
Anode; Fuell Cells 06, (2006) 16-20
Mazurek, M.; Benker, N.; Roth, C.; Fuess, H.; Binary Mixtures of Carbon Supported Pt and
Ru Catalysts for PEM Fuel Cells; Fuel Cells 06, (2006) 208-213
Meštric, H.; Eichel, R.-A.; Dinse, K.-P.; Ozarowski, A.; van Tol, J.; Brunel, L.C.; Kungl, H.;
Hoffmann, M.J.; Schönau, K.A.; Knapp, M.; Fuess, H.; Iron-oxygen vacancy defect
association in polycrystalline iron-modified PbZrO3 antiferroelectrics: Multifrequency
electron paramagnetic resonance and Newman superposition model analysis; Phys. Rev.
B 73, (2006) 184105
Mašlejová, A.; Ivaniková, R.; Svoboda, I.; Papánková, B.; Dlhán, L.; Mikloš, D.; Fuess, H.,
Boča, R.; Structural characterization and magnetic properties of
- 41 -

hexakis(imidazole)nickel(II)bis(formate), bis(chloroacetate), bis(2-chloropropionate) and
hexakis(1-methyl-imidazole)nickel(II)chloride dihydrate; Polyhedron 25, (2006) 1823-1830
Mikhailik, V. B. ; Kraus, H.; Wahl, D.; Ehrenberg, H., Mykhaylyk, M. S.; Optical and
luminescence studies of ZnMoO4 using vaccum ultraviolet synchrotron readiation,
Nucl.Instrum. Meth. A 562 (2006) 513-516.
Mikhailova, D.; Ehrenberg, H., Fuess, H., Synthesis, crystal structure and magnetic prop
erties of new indium rhenium and scandium rhenium oxides, In6ReO12 and Sc6ReO12; J.
Solid State Chem. 179 (2006) 3672-3680.
Mikhailova, D.; Ehrenberg, H.; Fuess, H.; Synthesis and structure determination of copper
perrhenate, CuReO4; Sol. State Chem. 179 (2006) 2004-2011
Mikhailova, D.; Ehrenberg, H.; Fuess, H.; Synthesis, crystal structure and magnetic
properties of new indium rhenium and scandium rhenium oxides, In6ReO12 and Sc6ReO12;
Sol. State Chem. 179, (2006) 3667-3675
Mikhailova, D.; Ehrenberg, H.; Fuess, H., Synthesis and structuredeterminationof copper
perrhenate, CuReO4, J. Solid State Chem. 179 (2006) 2004-2011.
Nikolowski, K. M.; Bramnik, N.; Baehtz, C.; Ehrenberg, H., Fuess, H.; In situ-XRD of Highly
Charged and Discharged LixNi0.8Co0.2O2 (x close to 0); ECS Transactions, vol. 1, issue
26, Rechargeable Lithium and Lithium-Ion Batteries (edt. J. Weidner) (2006) 17-26.
Öksüzoglu, R. M.; Yalcin, N.; Aktas, B.; Fuess, H.; FMR study of ultrahigh vacuum e-beam
evaporated Co23Cu77 nanogranular films: Magnetotransport properties; phys. stat. sol. (a)
203, (2006) 1573-1579
Papánkova, B.; Svoboda, I.; Fuess, H.; Bis(acetato-κO)diaquabis(1-methylimidazoleκN
3 )cobalt(II); Acta Cryst, E62, (2006) m1916-m1918
Qureshi, N.; Fuess, H.; Ehrenberg, H.; Hansen, T.C.; Ritter; C.; Prokes,K.; Podlesnyak, A.;
Schwabe, D.; Magnetic properties of the Kagome mixed compounds (CoxNi1-x)3V2O8,
Phys. Rev. B 74 (2006) 212407.
Rammeh, N.; Ehrenberg, H.; Fuess, H.; Cheikh-Rouhou, A.; Structure and magnetic
properties of the double-perovskites Ba2(B,Re)2O6 (B=Fe, Mn, Co and Ni); phys. stat. sol.
(c) 9, (2006) 3225-3228
Roth, C.; Benker, N.; Mazurek, M.; Scheiba, F.; Fuess, H.; Pt-Ru fuel cell catalysts
subjected to H2CO N2 and air atmosphere: an X-ray absorption study; Appl. Catalysis A,
(2006)
Toupance, T.; El Hamzaoui, H.; Jousseaume, B.; Riague, H.; Saadeddin, I; Campet, G.;
Brötz, J.; Polystannoxane; B; A New Route toward Nanoporous Tin Dioxide; Chem. Mater.
2006, 18, (2006) 6364-6372
- 42 -

Trots, D.M.; Skomorokhov, A.N.; Knapp, M.; Fuess, H.; High-temperature behaviour of
average structure and vibrational density of states in the ternary superionic compound
AgCuSe; Eur. Phys. J.B. 51, (2006) 507-512
Yonkeu, A.L.; Miehe, G.; Fuess, H., Goossens, A.M.; Martens, I.A.; A new overgrowth of
mazzite on faujasite zeolite crystal. Investigated by X-ray diffraction and electronic
microscopy; Microp. Mesop. Mater., 96, (2006) 396-404
Umbreen, S.; Brockhaus, M.; Ehrenberg, H.; Schmidt, B.; Norstatines from aldehydes by
sequential organocatalytic-amination and Passerini reaction, Eur.J.Org.Chem.(2006)
4585-4595.
Walha, I.; Cheikh-Rouhou, A.;Ehrenberg, H., Fuess, H.; Effect of calcium-deficiency upon
physical properties of La0.6Ca0.4MnO3, phys. stat. sol. (c)3 (2006) 3260-3265.
- 43 -

Chemical Analytics
The chemical analytics division deals with all kinds of topics concerned with qualitative,
semiquantitative and quantitative analytics of elemental composition and characterisation
of chemical binding in solid and liquid samples.
For solids, measurements with high spatial resolution are carried out by Electron Probe
Micro Analysis (EPMA) and Secondary Ion Mass Spectrometry (SIMS). The latter is also
used for thin film analysis with high depth resolution.
Average compositions of solids are analyzed by X-ray Fluorescence Analysis (XRF),
solutions of materials are measured by Atomic Absorption Spectrometry (AAS), ICP
Optical Emission Spectrometry (ICP-OES) and Gas Chromatography, coupled with high
resolution Mass Spectrometry (GC-MS).
Present research topics are:
Thin film speciation
In thin film technology, the identification of chemical compounds, phases and binding
conditions is of basic importance. In a collaboration with Physikalisch-Technische
Bundesanstalt in Berlin and institutes in Novosibirsk/Russia, thin films of boron
carbonitride and silicon carbonitride are prepared and characterized. The preparation
techniques are plasma enhanced chemical vapour deposition and sputtering (physical
vapour deposition). The chemical composition of the films is measured by SIMS. The
atomic binding states are investigated by Near Edge X-ray Absorption Fine Structure
(NEXAFS) measurements, partially in Total reflection and Glancing Incidence X-ray
Fluorescence (TXRF, GIXRF) geometry, by X-ray Photoelectron Spectrometry (XPS –
collaboration with Dr. A. Klein, Surface Science), and by Transmission Electron
Microscopy with Electron Energy Loss Spectrometry (TEM-EELS). The TXRF-NEXAFS
experiments are carried out at BESSY II.
In another project, thin films (nanofilms) of carbides of boron, silicon, titanium, and
tantalum are formed by hydrocarbon plasma immersion ion implantation, in collaboration
with Industrial Technology Center of Nagasaki. The chemical film composition is analyzed
by SIMS, the phase composition by X-ray diffraction. Film morphology and microstructure
are investigated by scanning electron microscopy and by atomic force microscopy.
- 44 -

Corrosion
Phenomena of aqueous corrosion of metals, depending on their chemical composition,
phase and structure, are investigated by electrochemical and trace analytical methods.
The methods include potential-time and current-potential (polarization, cyclic voltammetry)
measurements, Electrochemical Noise Analysis (ENA) and Electrochemical Impedance
Spectroscopy (EIS). Immersion tests with chemical analysis of the dissolved material are
carried out by e.g. Atomic Absorption Spectrometry and ICP Optical Emission
Spectrometry. The materials investigated are the metals aluminium, magnesium, and iron,
and alloys.
A special topic is the corrosion of thin films, formed by plasma and ion beam methods,
such as diamond-like amorphous carbon, or by sol-gel synthesis in combination with spin
coating, such as zirconium oxide. These films (on the nanometer scale, i.e. nanofilms)
suffer from microporosity which greatly influences the film/substrate corrosion
performance. The underlying corrosion mechanisms and the correlation between film
deposition parameters and corrosion protection ability are investigated.
Nanopores and nanowires
In collaboration with Gesellschaft für Schwerionenforschung (GSI), membranes or
microfilters are formed by irradiation of polymer foils (polycarbonate, polyimide) and
chemical etching the latent ion tracks to pores. These ion track filters (ITNF: ion track
nanofilters, when the pores have diameters < 100 nm) can be used for filtering liquids from
particles, collecting aerosols, for gas separation, and for analyzing small molecules and
molecular fragments by translocation.
In a further process step, the nanopores are galvanically filled with metals, such as copper
or gold, forming nanowires. The nanowires can be gained by dissolution of the polymer
template. Dimensions, surface topography, microstructure, and crystallinity are
investigated. Further, properties such as electrical conductivity and thermal stability are
studied. The wires decay upon heating to a chain of spheres (Rayleigh instability). This
effect is investigated.
Materials in Radiation Fields
In a number of applications, such as in nuclear facilities, particle accelerators and in
space, materials are exposed to energetic ionizing radiation. The irradiation may lead to a
degradation of the materials properties. Polymers are particularly sensitive towards
ionizing radiation. In a collaboration with GSI, polyimide and polyepoxide, which are
components of superconducting beam guiding magnets, were irradiated with relativistic
heavy ions and characterized for their properties, such as network degradation and
electrical conductivity. Another material is polycrystalline graphite, which is being used as
the target wheel and as the beam dump.
- 45 -

Collaborations
The above mentioned and a number of further topics, e.g., from semiconductor research
and from nuclear research, are investigated in collaboration with national institutes and
with research centers and institutes abroad, such as
� Physikalisch-Technische Bundesanstalt, Berlin;
� Gesellschaft für Schwerionenforschung, Darmstadt;
� Deutsches Kunststoff-Institut, Darmstadt;
� National Inst. of Advanced Industrial Science and Technology, Osaka, Japan;
� Industrial Technology Center of Nagasaki, Japan
� Rutherford Appleton Laboratory, Didcot, England
� Centre Interdisciplinaire de Recherche Ions Lasers, Caen, France
� Joint Institute for Nuclear Research, Dubna, Russia;
� Institute of Inorganic Chemistry, Novosibirsk, Russia;
� Institute for Water and Environmental Problems, Barnaul, Russia;
� Institute of Earth Crust, Irkutsk, Russia;
Staff Members
Head Prof. Dr. Wolfgang Ensinger
Research Associates Dr. Christiane Brockmann Dr. Stefan Flege
Dr. Peter Hoffmann Dr. Gunther Kraft
Dr. Falk Sittner
Technical Personnel Brunhilde Thybusch Dorothea Berres
Renate Benz
Secretary Antje Pappenhagen
PhD Students Mubarak Ali Olaf Baake
Thomas Herrmann Shafqat Karim
Jens von Ringleben Daniel Severin
Ruperto Ugas Tim Vogel
Mehdi Yekehtaz
Diploma Students Tim Seidl Christoph Ochs
Research Projects
Chemical and physical characterization of nanofilm systems (nanofilm speciation) (jointly
with PTB, Berlin; DFG 2005-2007)
Deposition and implantation of carbon from hydrocarbons by plasma immersion ion
implantation (DFG, 2005-2007)
- 46 -

Internal target experiments with highly energetic stored and cooled secondary beams at
the International Acceleration Facility, Darmstadt Ion Research and Antiproton Center (EU,
2005-2007)
Radiation resistance of insulating materials in superconducting magnets (GSI, 2004-2007)
Fabrication and characterization of gold nanowires (GSI, 2004-2007)
Contamination of dacha areas near of industrial complexes in Siberia (NATO, 2004-2006)
Separation of lithium and caesium isotopes from the primary coolant system of a
pressurized water reactor (EnBW AG Kernkraftwerk Philippsburg, 2005-2007)
Publications
Baake, O.; Öksüzoglu, R.M.; Flege, S.; Hoffmann, P.S.; Gottschalk, S.; Fuess, H.; Ortner,
H.M.; Determination of thickness, density and roughness of Co–Ni–Al single and multiple
layer films deposited by high-vacuum e-beam evaporation on different substrates,
Materials Characterization 57, 12 ( 2006 )
Brandt, R.; Ditlov, V.A.; Dwiwedi, K.K.; Ensinger, W.; Ganssauge, E.; Guo, S.-L.;
Haiduc, M.; Hashemi-Nezhad, S.R.; Khan, H.A.; Krivopustov, M.I.; Odoj, R.;
Pozharova, E.A.; Smirnitzki, V.A.; Sosnin, A.N.; Westmeier, W.; Zamani-Valasiadou, M.;
Interactions of relativstic heavy ions in thick heavy element targets and some unresolved
problems, E1-2005-167, Joint Institute for Nuclear Research, Dubna, (2006), 1
Cornelius, T. W.; Toimil-Molares, M. E.; Neumann, R.; Karim, S.; Finite-size effects in the
electrical transport properties of single bismuth nanowires, Journal of Applied Physics 100
(11) (2006 ) 114307
Cornelius, T.W.; Toimil-Molares, M.E.; Neumann, R.; Fahsold, G.; Lovrincic, R.; Pucci, A.;
Karim, S.; Quantum size effects manifest in infrared spectra of single bismuth nanowires,
Applied Physics Letters 88 (10) (2006) 103114
Ensinger, W. Corrosion and wear resistant coatings formed by ion beam techniques,
Chapter 18 in: Y. Peauleau (Ed.) Materials Surface Processing by Directed Energy
Techniques, Elsevier Science Publishing Company (2006)
Ensinger, W.; Formation of Diamond-Like Carbon Films by Plasma-Based Ion Implantation
and Their Characterization, Diamond and Frontier Carbon Technology 16 (2006) 1
F. Neubrech, T. Kolb, R. Lovrincic, G. Fahsold, A. Pucci, J. Aizpurua, T. W. Cornelius, M.
E. Toimil-Molares, R. Neumann, S. Karim, Resonances of individual metal nanowires in
the infrared, Applied Physics Letters 89 (25) (2006 ) 253104
Hanefeld, P.; Sittner, F.; Ensinger, W.; Greiner, A.; Investigation of the ion permeability of
poly(p-xylylene) films, e-Polymers 26 (2006) 1
Höchbauer, T.; Misra, A.; Nastasi, M.; Mayer, J.W.; Ensinger, W.; Formation of hydrogen
complexes in proton implanted silicon and their influence on the crystal damage, Nucl.
Instr. Meth. Phys. Res. B242 (2006) 623
- 47 -

Hoffmann, P.; Non-Invasive Identification of Chemical Compounds by EDXRS, in: Practical
X-Ray Fluorescence Analysis (Eds.: B. Beckhoff, B. Kanngießer, N. Langhoff, R. Wedell,
H. Wolff) Springer, Berlin – Heidelberg (2006) 769
Karim, S.; Toimil Molares, M.E.; Maurer, F.; Miehe, G.; Ensinger, W.; Liu, J.;
Cornelius, T.W.; Neumann, R.; Synthesis of gold nanowires with controlled
crystallographic characteristics, Appl. Phys. A 84 (2006) 403
Karim, S.; Toimil-Molares, M. E.; Balogh, A.G.; Ensinger, W.; Cornelius, T.W.; Khan, E.U.;
Neumann, R.; Morphological evolution of Au nanowires controlled by Rayleigh instability,
Nanotechnology 17 (2006) 5954
Kraft, G.; Flege, S.; Reiff, F.; Ortner, H.M.; Ensinger, W.; Analysis of the notches of ancient
serrated denars, Archaeometry 48, 4 (2006) 605
Kraft, G.; Flege, S.; Reiff, F.; Ortner, H.M.; Ensinger, W.; Electron-probe microanalysis
investigations of Roman coin silvering techniques, Microchimica Acta 155 (2006) 179
Liu, J.; Duan, J.L. ; Toimil-Molares, M. E.; Karim, S.; Cornelius, T.W.; Dobrev, D.;
Yao, H. J.; Sun, Y. M.; Hou, M. D.; Mo, D.; Wang, Z. G.; Neumann, R.; Electrochemical
fabrication of single-crystalline and polycrystalline Au nanowires: the influence of
deposition parameters, Nanotechnology 17 (8) (2006) 1922
Ortner, H.M.; Kraft, G.;Topochemische Untersuchungen antiker versilberter Münzen, GIT
Labor-Fachzeitschrift 05/2006, 436
Zimmermann, T.; Ensinger, W.; Schmidt, T.C.; Depletion solid-phase microextraction for
the evaluation of fiber-samples partition coefficients of pesticides, J. Chromatography A
1102 (2006) 51
- 48 -

Theoretical Materials Science
Teaching by this division addresses the atomistic foundations of materials science,
including the concepts underlying their representation, from the theoretical physics point of
view. Research focuses on materials modelling, being a powerful tool for materials
development. Experimental results will be understood, and predictions of further
observations given, in the light of theoretical evidence, both to aid the optimization of the
properties or the performance of materials already in use and to guide the design of novel
materials with properties, or behaviour, required in future engineering applications.
Current investigations centre on the following classes of materials:
Transition metals and related alloys
For this class of materials, represented by Ta and Fe or, respectively, steels, the goal is
examining their suitability for structural components of high-power spallation neutron
sources that are exposed to intense proton beams. Irradiation-induced hydrogen
production under the operating conditions of the envisaged European spallation source is
predicted to generate high internal concentrations of atomic hydrogen which, further
enhanced by stress-driven hydrogen accumulation near microstructural cracks, may lead
to a severe degradation of the mechanical properties of steel, whereas no noticeable
deterioration is to be expected in the case of tantalum.
High-temperature superconductors
For this class of materials, typified by YBa2Cu3O7 and Bi2Sr2Ca2Cu3O10 in thin-film or bulk
form, great interest is directed towards investigating extended defects (e.g. low-angle grain
and twin boundaries) which are considered as weak-links between superconducting grains.
There are two principal aims: (i) exploring the connection between the electromagnetic
response (e.g. the current-voltage relation) and the characteristic defect morphology so as
to obtain insight into constitutive parameters of superconducting films; (ii) searching for
possibilities to improve the current-carrying capability of superconducting materials, which
is limited by the above-mentioned types of defect. Preliminary studies of novel
heterostructures involving superconductor strips with a single grain boundary defect,
placed in open magnetic cavities, show that magnetic shielding here is a promising way
forward. Another field of research addresses the interaction between electromagnetic
radiation and multilayered heterostructures made up of superconductors as well as a range
of different classes of materials with a view to examining their suitability for novel photonic
crystals. Of special interest are materials whose properties can be controlled by external
parameters and fields.
Organic semiconductors
For this class of materials, represented by Alq3, emphasis is placed on real-time modelling
of the charge transfer by injected carriers and on a theoretical analysis of thermally
stimulated luminescence phenomena with the aim of extracting, in conjunction with
experiments, information about the electronic structure of inherent traps so as to assist
technological exploitation and further materials development. Some of the most important
features to be taken into account hereby are the field-dependence of the mobilities of the
charge carriers addressed as well as the field- and temperature dependences of the
injection barriers present, apart from allowing for the variation of the distribution of traps in
space and depth.
- 49 -

Ferroelectrics
For this class of materials, typified by BaTiO3 , attention is focussed on the process of
ageing, i.e. the gradual change of materials properties with time, isothermal conditions and
absence of external mechanical loads implied. This process manifests itself in alterations
of static and, respectively, kinetic characteristics such as the clamping pressure exerted on
the walls of ferroelectric domains and the asymmetry of the electrical conductivity
regarding current flow parallel or antiparallel to the direction of the spontaneous
polarization; phenomena, which may be explained in terms of migration of charged point
defects under the influence of internal or external electric fields. Preliminary results
obtained with a drift-diffusion approach suggest that the experimentally observed drastic
rise of the clamping pressure with time is indeed controlled by a mechanism of this kind.
The theories underlying these investigations range from microscopic to macroscopic; their
realizations employ analytical as well as computational techniques.
Staff Members
Head H.E. The Hon. Prof. Dr. Dr.habil. Hermann Rauh,
M.A., C.Phys., F.Inst.P., F.I.M., O.I.A.
Research Associates Dr. Yuri A. Genenko, D.Sc.
Dr. Sergey V. Yampolskii
Postgraduate Dipl.-Phys. Frederik Neumann
Secretary N.N.
Visiting Scientists Dr. Alexei V. Golovchan
Prof. Dr. Igor L. Lyubchanskii
Dr. Galina I. Yampolskaya
Research Projects
Electrodynamics of Macroscopic Magnet/Superconductor Heterosystems (German
Research Foundation (DFG), 2003-2006)
Kinetic Modelling of the Charge Transfer in Organic Semiconductors and Ionic Conductors
(Collaborative Research Centre (SFB) ”Electric Fatigue in Functional Materials”, 2003-
2006, with Prof. Dr. H. v. Seggern, Darmstadt University of Technology)
Publications
Genenko, Y.A.; Rauh, H.; Novel superconductor/magnet resonant configurations:
Exact analytic representations of the Meissner state and the critical state, J. Phys.: Conf.
Ser. 43 (2006) 568.
- 50 -

Lupascu, D.C.; Genenko, Y.A.; Balke, N.; Aging in ferroelectrics, J. Amer. Ceramic Soc. 89
(2006) 224.
Neumann, F.; Genenko, Y.A.; v. Seggern, H.; The Einstein relation in systems with trapcontrolled
transport, J. Appl. Phys. 99 (2006) 013704.
Neumann, F.; Genenko, Y.A.; Melzer, C.; v. Seggern, H.; Self-consistent theory of unipolar
charge-carrier injection in metal/insulator/metal systems, J. Appl. Phys. 100 (2006) 084511.
Nikolaenko, Y.M.; Medvedev, Y.V.; Genenko, Y.A.; Ghafari, M.; Hahn, H.; Interface thermal
resistance of a nanostructured FeCoCu film and a Si substrate, phys. stat. sol. (c) 3 (2006)
1343.
Yampolskii, S.V.; Genenko, Y.A.; Rauh, H.; Snezhko, A.V.; The Bean model of the critical
state in a magnetically shielded superconductor filament, J. Phys.: Conf. Ser. 43 (2006)
576.
Yampolskii, S.V.; Yampolskaya, G.I.; Rauh, H.; Magnetic dipole-vortex interaction in a
bilayered superconductor/soft-magnet heterostructure, Europhys. Lett. 74 (2006) 334.
- 51 -

Materials Modelling
The research activities of the Materials Modelling Division are directed towards the
investigation of materials properties and processing by atomic scale computer simulations.
Materials of interest include functional nanoparticles, ferroelectrics, transparent and
organic semiconductors as well as nanostructured metals. We are combining a variety of
methods depending on time and length scales involved in the corresponding problem.
Quantum mechanical calculations based on density functional theory are used for
electronic structure calculations. Large-scale molecular dynamics with analytical
interatomic potentials are the method of choice for studying kinetic processes and plastic
deformation. Kinetic lattice Monte-Carlo simulations are extensively used for simulations of
diffusional and transport processes on long time scales. The group is operating two
parallel PC-clusters and has access to the Hessian High Performance Computers in
Frankfurt and Darmstadt.
The current research areas are:
• Structure and mobility of point defects in transparent conducting oxides and
ferroelectrics
• Thermodynamic and kinetic properties of functional nanoparticles
• Charge carrier transport in organic light-emitting devices
• Mechanical properties of nanocrystalline materials
• Development of reactive interatomic potentials for compound systems
Besides the mandatory teaching of an undergraduate course the Materials Modelling
Division is currently offering a 2-semester course on atomic scale methods for materials
simulations and is contributing to the practical course. In 2006 Paul Erhart graduated as
first PhD-student of the Materials Modelling division. He was awarded with the Graduate
Student Award Gold Medal at the MRS 2006 Fall Meeting in Boston and now has joined
Lawrence Livermore Lab as a postdoctoral fellow.
Staff Members
Head
Dr. Karsten Albe, Assistant Professor
PhD Students Dipl.-.Ing. Michael Müller
Dipl.-.Ing. Paul Erhart
Diploma Students Johan Pohl
Peter Agoston
Technical Personnel Andreas Hönl (Trainee) Dennis Ratley (apprentice)
Kathleen Feustel (apprentice)
Secretary
Renate Hernichel
- 52 -

Guest Scientist
Research Projects
Prof. Kai Nordlund, PhD; University of Helsinki, Finland
Niklas Juslin, MSc; University of Helsinki, Finland
Tommi Järvi, MSc; University of Helsinki, Finland
Petra Träskelin, MSc; University of Helsinki, Finland
Eero Kesälä; University of Helsinki, Finland
Atomistic computer simulations of defects and their mobility in metal-oxides (DFG-SFB
595, Project C2, 2003-2006 )
Atomistic modelling of metal oxide and -carbide nanoscale systems (DAAD, PPP Finland,
2003-2006)
Polymeric nitrogen (DFG, Al 578-3, 2005-2007)
Plasticity of nanocrystalline metals and alloys, (DFG FOR 714, 2006 – 2009)
Metallic nanoglasses (DFG Al 578-6, 2006 – 2007)
Publications
Zhao, S.J.; Albe, K.; Hahn, H.; Grain size dependence of the bulk modulus of
nanocrystalline nickel, Scripta Mat. 55 (2006) 473-476)
Erhart, P.; Juslin, N.; Goy, K.; Nordlund, R.; Müller, M.; Albe, K.; Analytic bond-order
potential for atomistic simulations of zinc oxide, J. Phys. Cond. Matter 18 (2006) 8565-
6605
Erhart, P.; Albe, K.; Diffusion of zinc vacancies and interstitials in zinc oxide, Appl. Phys.
Lett. 88 (2006) 201918
Erhart, P.; Albe, K.; Klein, A.: First-principles study of intrinsic point defects in Zn0: Role of
band structure, volume relaxation and finite size effects, Phys. Rev. B 73 (2006) 205203
Erhart, P.; Albe, K.; First-principles study of migration mechanisms and diffusion of oxygen
in zinc oxide, Phys.Rev.B 73 (2006) 115207
Jin, Z.-H.; Gumbsch, P.; Ma, E.; Albe, K.; Lu, K.; Hahn, H.; Gleiter, The interaction
mechanism of screw dislocations with coherent twin boundaries in different face-centred
cubic metals, Scripta Mat., 54 (6) (2006) 1163-1168
- 53 -

Materials for Renewable Energies
In December 2004, the new group Renewable Energies formed at the Institute for
Materials Science. At present, research focuses on low-temperature fuel cells and related
electrocatalysis using advanced ex-situ, and in particular, operando techniques for the
detailed structural and electrochemical characterization of nanoscale catalysts.
Techniques applied on the structural side include X-ray diffraction (XRD), X-ray absorption
spectroscopy (XAS), and transmission electron microscopy (TEM), whereas
electrocatalytic activities are measured using cyclic voltammetry (CV), electrochemical
impedance spectroscopy (EIS), and single cell fuel cell tests.
Recent projects concern the systematic investigation of the membrane-electrode assembly
in polymer electrolyte fuel cells (PEMFC) before and after use, and its optimization
according to the requirements for efficient operation. In this project, a new methodology for
TEM characterization has been developed, which provides fascinating insights into the
MEA structure. In another approach, a special in-situ fuel cell has been developed and
successfully applied at beamlines X1, Hasylab, Hamburg, and at BM29 and ID24 at ESRF,
Grenoble. First time-resolved operando experiments have been performed shedding light
on fundamental mechanisms taking place during real fuel cell operation.
The group has established various national and international cooperations in the fuel cell
community. In a joint project with Tsinghua University, Beijing, and TUM, Munich, the
application of carbon nanotube materials in PEMFC and its effect on the three-phase
boundary is investigated. In cooperation with David Ramaker and his group at George
Washington University, a novel data analysis technique has been developed, which
allowes us to monitor changes in catalyst structure and adsorbate coverage during real
cell operation. Collaborative agreements exist between the group and several companies,
large scale facilities as well as national and international universities. These are largely
covered by funds from the German Science foundation (DFG) and the BMBF.
Teaching activities in 2006 included the regular curricula lecture “Methods in Materials
Science” and the linked practical course. The group`s research interests are covered by a
lecture on “Fuel Cells – from fundamentals to application” and a practical course “X-ray
absorption spectroscopy – fundamentals and data analysis” (joint workshop with Prof.
David Ramaker). Furthermore, a workshop on “Scientific work and presentation skills”
(with Dr. I. Kinski) is offered on request.
Staff Members
Head
Secretary
Dr. Christina Roth
Maria Holzmann (joint with Prof. Fuess)
PHD students Dipl.-Ing. Virginie Croze
Dipl.-Ing. Susanne Zils
Students Guillaume Savoye
Guest Scientists
Dipl.-Ing. Frieder Scheiba
(joint with Prof. Fuess)
Dipl.-Ing. Julia Melke (extern, ISE)
Dipl.-Ing. Marcelo da Carmo, IPEN, Sao Paulo (with Prof. Fuess)
- 54 -

Research Projects
Characterization of the three-phase boundary in differently-synthesized membraneelectrode
assemblies (DFG Sino-German project 2004-2006)
In-situ X-ray diffraction and X-ray absorption spectroscopy for investigation of the cathode
catalyst in a working fuel cell (DFG project 2005-2008)
Structural investigation of membrane-electrode assemblies in fuel cells using ESEM (DFG
project 2006-2009)
Chemical and morphological characterization of nanostructured electrocatalyst systems
supported on modified carbon black and produced by different methods (DAAD-CAPES
Brazil 2006-2007)
Publications
Mazurek, M.; Benker, N.; Roth, C., Buhrmester, Th.; Fuess, H.; Electrochemical
impedance and X-ray absorption spectroscopy (EXAFS) as in-situ methods to study the
PEMFC anode, Fuel Cells 6 (1) (2006) 16-20.
Benker, N.; Roth, C.; Mazurek, M.; Fuess, H.; Synthesis and characterisation of ternary
Pt/Ru/Mo catalysts for the anode of the PEM fuel cell, J. New Mat. Electrochem. Sys. 9
(2006) 121-126.
Mazurek, M.; Benker, N.; Roth, C.; Fuess, H.; Structural and electrochemical investigation
of binary mixtures of carbon-supported Pt and Ru catalysts for PEM fuel cells, Fuel Cells 6
(2006) 208-213.
Scheiba, F.; Scholz, M.; Lin, C.; Roth, C.; Cremers, C.; Qiu, X.; Stimming, U.; Fuess, H.;
On the suitability of hydrous ruthenium oxide supports to enhance intrinisic proton
conductivity in direct methanol anodes, Fuel Cells 6 (2006) 439-446.
Cao, L.; Scheiba, F.; Roth, C.; Schweiger, F.; Cremers, C.; Stimming, U.; Fuess, H.; Chen,
L.; Zhu, W.; Qiu, X.; Novel nano-composite Pt/RuO2·xH2O/CNT catalysts for DMFC,
Angew. Chem. Int. Ed. 45 (2006) 5315-5319.
Roth, C.; Mazurek, M.; Benker, N.; Katalysatoren im Baukastensystem, Thema Forschung
2/2006, 58-63.
- 55 -

Joint Research Laboratory
Nanomaterials
The Joint Research Laboratory Nanomaterials was established in 2004 to enhance the
cooperation between the Institute for Nanotechnology at the Forschungszentrum Karlsruhe
and the Institute of Materials Science at the Technische Universität Darmstadt. The startup
to establish the laboratory was provided by both institutions. Scientific personell is
financed by the Forschunszentrum Karlsruhe and by external grants of funding agencies in
Germany and of the EU as well as by industrial cooperations. The laboratory interacts in
several areas with research groups in Materials Science and Chemistry. The research
activities are concentrated in the area of nanoparticulate systems, their synthesis and
processing, microstructural characterization and their properties. The focus is currently on
developing nanoporous structures as bulk materials and thin films on a variety of
substrates for developing catalyst support materials and catalysts, gas sensors and
templates for the growth of light-harvesting molecular structures (porphyrines) and the
development of alternative solar cells for low light conditions. An additional engineering
focus of the research is on the stability of nanostructured materials under operation
conditions, such as high temperatures and gas environments, as well as the study of
mechanical performance of nanoporous structures. The nanomaterials are prepared using
Chemical Vapor Synthesis and Nebulized Spray Pyrolysis starting from metal-organic
precursors and metal salts. Using these methods a wide range of nanostructures can be
synthesized. In addition to several synthesis systems, characterization equipment is
available including X-ray diffraction, nitrogen adsorption, light scattering and Zeta potential
and gas chromatography.
Staff Members
Head
Research Associates Dr. Hermann Sieger
Secretary
Prof. Dr.-Ing. Horst Hahn (Director Institute for Nanotechnology)
Renate Hernichel
PhD Students Dipl.-Ing. Thorsten Enz
Dipl.-Ing. Sebastian Gottschalk
Dipl.-Ing. Peter Marek
Dipl.-Ing. Simon Bubel
Diploma Students Johannes Kostka
Guest Scientists
Jens Suffner
Prof. Ali Beitollahi
Dr. V. Mahender
Dr. M. Karajai
- 56 -
Dr. Jens Ellrich
Dr. Holger Schmitt
Dipl.-Ing. Jens Suffner
Dipl.-Ing. Azad Jaberidarbandi
Dipl. Phys. Anna Castrup
Ravi Mohan Prasad

Research Projects
Defect structure and diffusion in ferroelectric materials (SFB 595 2003 – 2006)
Processing of Nanostructured Materials through Metastable Transformations Namamet
(EU 2004 – 2009)
DIRAC secondary-Beams (EU/GSI 2005 – 2008)
Plastizität in Nanokristallinen Metallen und Legierungen, Teilprojekt 5, Aufklärung von
Verformungsmechanismen mittels Synchrotron-Röntgenstrahlung (DFG 2006 – 2009)
Metallische Nanogläser (DFG 2006 – 2008)
Publications
Enz, T.; Winterer, M.; Stahl, B.; Bhatacharya, S.; Miehe, G.; Foster, K.; Fasel, C.; Hahn,
H.; Structure and magnetic properties of iron nanoparticles stabilized in carbon, Journal of
Applied Physics, 99 (4) (2006) 044306
Sieger, H.; Suffner, J.; Raju, A.R.; Miehe, G.; Hahn, H.; Thermal Stability of
Nanocrystalline Sm2 O3 and Sm2 O3 –MgO, Journal Amer. Ceram. Soc. 89 (2006) 979-984
Marek, P.; Balaban, S.; Nachrichten aus der Chemie, 54, (2006) 1072-1077
Jin, Z. H.; Gumbsch, E.; Albe, K.; Hahn, H.; Gleiter, H.; The Interaction mechanism of
screw dislocations with coherent twin boundaries in different face-centred cubic metals,
Scripta Materialia, 54 ( 2006) 1163-1168
Kruk, R.; Ghafari, M.; Hahn, H.; Birringer, R.; Michels, D.; Kmiec, R.; Marszalek, M., Grainsize-dependent
magnetic properties of nanocrystalline Gd., Physical Review B, 2006, 73
(2006) 054420
Schmitt, H.; Ghafari, M; Kruk, R.; Schmitt, L.A.; Ellrich, J.; Hütten, A.; Hahn, H.; Interfacial
microstructure of Fe/AlOx/Fe-magnetic tunnel junctions in high resolution, Applied Physics
Letters 88 (2006) 122505
Akurati, K.K.; Bhattacharya S.S.; Winterer, M.; Hahn, H.: Synthesis, characterization and
sintering of nanocrystalline titania powders produced by chemical vapour synthesis, J.
Phys. 39 (2006) 2248-2254
Yin, S.; Xu, M.X.; Yang, L.; Liu, F.J.; Rösner, H.; Hahn, H.; Gleiter, H.;Schild, D.; Doyle,S.;
Liu, T.; Hu T.D.; Takayama-Muromachi, E.; Jiang J.Z.; Absence of ferromagnetism in bulk
polycrystalline Zn0.9Coo.1O. Phys.Rev. B73 (2006) 224408
Zhao, Shi-Jin.; Albe, K.; Hahn, H.; Grain size dependence of the bulk modulus of
nanocrystalline nickel, Scripta Materialia 55 (2006) 473-476
Brehm, J.; Winterer, M.; Hahn, H.; Synthesis and Structure of Nanocrystalline Transparent
Conducting Zinc Oxides, J. Appl. Phys. 100 (2006) 064311
Bansal, C.; Sarkar, A.K.; Mishra, A:K.; Abraham, T.; Lemier, Ch.; Hahn, H.; Electronically
tunable conductivity of a nanoporous Au-Fe alloy, Scripta Materialia 56 (2006) 705-708
Padmanabhan, K.A.; Dinda, G.P.; Hahn, H.; Gleiter, H.; Inverse Hall-Petch effect and grain
boundary sliding controlled flow in nanocrystalline materials, Accepted in Materials
Science and Engineering A (2006)
- 57 -

Collaborative Research Center (SFB)
„Electric Fatigue in Functional Materials“
Phase II: Jan. 2007 – Dec. 2010
www.sfb595.tu-darmstadt.de
The center for collaborative studies (Sonderforschungsbereich) has been awarded by the
Deutsche Forschungsgemeinschaft in 2002 to TU Darmstadt and is centered in the
Department of Materials and Earth Sciences with important contributions from the
Department of Chemistry and the Departments of Civil Engineering, Mechanical
Engineering as well as the Mechanical Engineering Department of the University of
Karlsruhe. The center was renewed in 2006 and has recently started its second four-year
funding period.
It is comprised of a total of 19 projects and financial resources for four years of about 8
Mio. €. The center has an active guest program with guests visiting from 2 days to 3
months. For specific information, please contact either the secretary of the center, Mrs.
Gila Voelzke, or the director of the center, Prof. Jürgen Rödel.
Contact:
Office: SFB 595: Electrical Fatigue in Functional Materials,
Institute of Materials Science
Petersenstr. 23
64287 Darmstadt
Tel.: +49-6151-16-6362, 6315
Fax: +49-6151-16-6363, 6314
Building/Room: L201 / 55
E-mail: roedel@ceramics.tu-darmstadt.de
Voelzke@ceramics.tu-darmstadt.de
Electrical fatigue in functional materials encompasses a set of phenomena, which lead to
the degradation of materials with an increasing number of electrical cycles. Electrical
cycling leads to both reversible and irreversible currents and polarisations. Ionic and
electronic charge carriers interact with each other and with microstructural elements in the
bulk as well as at interfaces (grain boundaries and domain walls) and interphases
(electrode/electrolyte). This in turn causes local changes in the distribution of electric
currents and electric potentials. As a consequence local overloads and material
degradation ensues and leads to irreversible loss of material properties. This material
degradation can lead finally to mechanical damage as well as to dissociation reactions.
The basic phenomena of electrical fatigue are not yet understood on a microscopic level.
The goal of this center of excellence in the second phase is the understanding of the
mechanisms leading to electrical fatigue. An understanding of the experimental results is
supported by concurrent materials modelling which is geared to encompass different time
and length scales from the material to the component.
A key feature of the center is therefore the steady comparison between theory and
experiment. This is utilized to find the physico-chemical origins of electrical fatigue as well
as to develop strategies for new materials and improved material combinations. The
- 58 -

materials of interest are ferroelectrics, electrical conductors (cathode materials for lithium
batteries and transparent conducting oxides) and semiconducting polymers.
Projects:
Division A: Synthesis
A1
P.I. : Prof. J. Rödel
Topic: Manufacturing of textured ceramics actuators with high strain
A2
P.I. : Prof. M. J. Hoffmann,
Topic: Manufacturing and characterization of PZT-ceramics under dc loading
A3
P.I. : Prof. W. Jaegermann
Topic: Boundary layers and thin films of ionic conductors: Electronic structure,
electrochemical potentials, defect formation and degradation mechanisms
A4
P.I. : Prof. R. Riedel
Topic: Novel functional ceramics using anionic substitution in oxidic systems
A5
P.I.: Prof. M. Rehahn
Topic: Synthesis of semiconducting model polymers and their characterization before and
after cyclic electric fatigue
Division B: Characterization
B1
P.I.: Dr. R.-A. Eichel / Prof. K.-P. Dinse
Topic: EPR-Investigations of defects in ferroelectric ceramic material
B2
P.I.: Dr. Dr. A. G. Balogh
Topic: Investigations of the defect structure and diffusion in ferroelectric materials
B3
P.I.: Prof. H.-J. Kleebe / Prof. H. Fueß
Topic: Structural investigations into the electrical fatigue in PZT
B4
P.I.: Dr. H. Ehrenberg
Topic: In-situ investigations of the degradation of intercalation batteries und their modelling
- 59 -

B7
P.I.: Prof. H. v. Seggern / Dr. A. Klein
Topic: Dynamics of electrical properties in fatigued PZT
Division C: Modelling
C1
P.I.: Prof. K. Albe
Topic: Quantum mechanical computer simulations for electron and defect structure of
oxides
C2
P.I.: Prof. K. Albe
Topic: Atomistic computer simulations of defects and their mobility in metal oxides
C3
P.I.: Prof. R. Müller / Prof. W. Becker
Topic: Microscopic investigations into defect agglomeration and its effect on the mobility of
domain walls
C5
P.I.: Dr. Y. Genenko / Prof. H. v. Seggern
Topic: Phenomenological modelling of bipolar carrier transport in organic semiconducting
devices under special consideration of injection, transport and recombination phenomena
Division D: Component properties
D1
P.I.: Professor J. Rödel / Dr. T. Granzow
Topic: Mesoscopic and macroscopic fatigue in doped ferroelectric ceramics
D3
P.I.: Dr. A. Klein
Topic: Function and fatigue of conducting electrodes in organic LEDs and piezoceramic
actuators
D4
P.I.: Dr. Ch. Melzer / Professor H. v. Seggern
Topic: Fatigue of organic semiconductor components
D5
P.I.: Professor W. Jaegermann
Topic: Processing and characterization of Li-ion thin film batteries
- 60 -

Reports of Research Activities
High strength metastable materials with enhanced ductility
J. Das, S. Pauly, F. Ettingshausen, K. B. Kim, J. Eckert
The recent developments in the area of metastable metallic materials like bulk metallic
glasses and nanostructured alloys have revealed the large potential of Cu-, Ti- and Zrbased
glassy and nanostructured (nano-eutectic) composites for a variety of applications
as high specific strength structural materials. Previous investigations on the room
temperature deformation behavior have shown that the respective volume fractions of
dendrites and nano-/ultrafine eutectic matrix govern the overall strength and ductility of the
material. The development of new alloys derived from glass-forming alloy compositions
with homogeneous nano-/ultrafine eutectic microstructure and bulk metallic glasses with
high strength and enhanced room temperature plastic deformability was the major aim of
the work in 2005. Ultimately, this should open up the possibility to develop tailor-made
microstructures in order to improve the mechanical properties of such novel materials.
As an example for ductile bulk metallic glasses, Cu50Zr50 and Cu47.5Zr47.5Al5 2 mm diameter
(∅) rods were investigated in detail using x-ray diffraction (XRD), differential scanning
calorimetry (DSC), scanning electron microscopy (SEM) and transmission electron
microscopy (TEM). Even though the structure of Cu50Zr50 was found to be amorphous
through XRD and DSC studies, traces of very tiny crystallites were found to be randomly
present in the glassy matrix. The size of these crystallites is about 2 – 5 nm as measured
from the lattice fringes observed in high resolution images. Cu47.5Zr47.5Al5 gives no hint for
the presence of any distinguishable crystallites like Cu50Zr50. However, the selected area
diffraction pattern from the overall structure shows a weak contrast overlapping on the
amorphous ring (Fig. 1, inset). The high resolution image of this alloy reveals no lattice
fringes of crystals. Maximum 3 – 4 atomic layers are observed to have a regular
arrangement without any long-range order.
Fig. 1: High resolution TEM image of a
Cu47.5Zr47.5Al5 glass. Inset: selected area
diffraction pattern from such a microstructure.
Cu50Zr5
Cu47.5Zr47.5Al5
Cu47.5Zr47.5Al5
Fig. 2: Compressive stress-strain curves of Cu50Zr50 and
Cu47.5Zr47.5Al5 glassy rods. Inset: true stress-true strain
curve of Cu47.5Zr47.5Al5 showing “work-hardening”-like
behavior.
- 61 -

The glass transition temperature (Tg) of Cu50Zr50 and Cu47.5Zr47.5Al5 2 mm∅ rods are
estimated to be 671 K and 698 K, respectively. The supercooled liquid region (∆Tx) for
Cu50Zr50 and Cu47.5Zr47.5Al5 is 46 K and 74 K, respectively. This proves that addition of Al
increases the glass-forming ability of binary Cu50Zr50. The resulting Cu47.5Zr47.5Al5 glass
exhibits high strength (2265 MPa) together with a large room temperature ductility of up to
18%, as depicted in Fig. 2. After yielding a strong increase in the flow stress is observed
during deformation indicating a “work-hardening” like behavior.
In recent years, a large number of high strength and ductile Ti-base nanocomposites with
bimodal distribution of micrometer-sized primary bcc β-Ti dendrites / primary FeTi(Co)
phase distributed in a nano-/ultrafine eutectic matrix has been reported. Similar properties
have been achieved by tailoring the eutectic structure without any micrometer-sized
toughening phase. For example, (Ti0.705Fe0.295)100-x Snx (x = 0 and 3.85) ultrafine eutectics
were prepared by slow cooling from the melt through cold crucible casting into 6 mm
diameter rods. The microstructure of both alloys exhibits an eutectic consisting of A2 (β-Ti)
and B2 (FeTi) phases. Ti67.78Fe28.36Sn3.85 shows pronounced colony boundaries and
equiaxed colonies with a cell size of 50 – 10 µm (Fig. 3). The growth of the FeTi phase is
rather parallel at the center of the colony with an interlamellar spacing (λ) of 300 nm, which
is more refined than the binary Ti70.5Fe29.5 eutectic (λ = 500 nm). At the colony boundary
the growth of the FeTi phase becomes restricted in the longitudinal direction and becomes
coarser. TEM investigations suggest that both alloys exhibit the same orientation
relationship ([110]β-Ti || [110]FeTi) and [200]β-Ti || [200]FeTi) between the A2 and B2 structures
(inset to Fig. 3). XRD analysis revealed that there is an increase in the difference between
the lattice parameter values (δ) of the A2 and B2 structures from 0.017 nm (Ti70.5Fe29.5) to
0.028 nm (Ti67.78Fe28.36Sn3.85).
Ti67.78Fe28.36Sn3.85 exhibits a significantly improved ductility reaching a fracture strain of εf =
9.6 % compared with εf = 2.6% for Ti70.5Fe29.5. The fracture strength is σ max = 1935 MPa
for Ti70.5Fe29.5 and σ max = 2260 MPa for Ti67.78Fe28.36Sn3.85 (Fig. 4). Possibly a higher lattice
mismatch in the ternary alloy (δ = 0.028 nm) between the A2 and B2 structures introduces
coherency strains at the interface, which may be a favorable condition to absorb the
dislocations emitted from the β-Ti(Fe,Sn) phase during deformation. This, in turn, allows to
emit dislocations or activates slip in the FeTi phase providing better slip transfer across the
interface.
Fig. 3: SEM (secondary electron) image of the
Ti67.79Fe28.36Sn3.85 nano-/ultrafine eutectic. Inset:
SAED pattern showing diffractions from A2 (β-Ti)
and B2 (FeTi) structures.
Fig. 4: Compressive engineering stress-strain
curves of Ti70.5Fe29.5 and Ti67.79Fe28.36Sn3.85
nano-/ultrafine eutectics.
- 62 -

Transition of crack closure mechanism in Ti-6Al-4V
Arne Kriegsmann and Clemens Müller
During cyclic loading, fatigue crack closure occurs when crack faces are in contact before
minimum load. It is assumed that no crack-tip damage occurs while crack faces are in
contact, so this portion of the load cycle is ineffective for fatigue crack growth. Therefore,
the effective stress intensity range ∆Keff at the crack tip and thereby the crack propagation
rate decreases.
Fatigue crack closure can result from residual plastic deformations remaining in the wake
of an advancing crack, fracture surface roughness or corrosion deposits in the crack wake.
These three closure mechanisms are called plasticity induced closure, roughness induced
closure and oxide induced closure, respectively.
500 µm
25 µm
Fig. 1a: Lamellar microstructure Fig. 1b: Equiaxed microstructure
Fig. 1c: Transition from coarse lamellar (left) to equiaxed (right) microstructure
At higher values of ∆K, material at the crack tip experiences large tensile plastic strains
which are not reversed upon unloading. Tensile residual displacements left in the crack
wake cause plasticity induced crack closure. At low stress intensity levels crack growth
proceeds locally in one slip system, leading to a kinked crack and finally to roughness
induced crack closure. Thus, when determining the crack propagation threshold a change
from plasticity induced to roughness induced crack closure takes place for most
microstructures. This transition and its consequences on crack closure level is still not fully
understood.
Ti-6Al-4V lamellar microstructures (Fig. 1a) cause roughness induced crack closure even
at high ∆K values. At the same ∆K, equiaxed microstructures (Fig. 1b) lead to plasticity
induced crack closure resulting in lower Kop values. In this investigation a heat treatment
using a temperature gradient was used to produce specimens showing a sharp transition
(Fig. 1c) from lamellar to equiaxed microstructure. During fatigue crack growth this
- 63 -

transition allows to investigate at constant loading ∆K, the change in crack closure due to
microstructural change.
The results of crack closure measurements are expressed by the development of Kop over
the crack distance from the transition (Fig. 2). It is obvious that the slope of the linear
approximation is different for the two crack propagation directions (equiaxed to lamellar
and lamellar to equiaxed). The difference in the slope for the two crack propagation
directions indicates that there is a “microstructual history effect”, which affects crack
closure and therefore crack growth rate too, leading to direction depending crack
propagation rates.
K op [MPam 1/2 ]
8
7
6
5
4
3
2
m=-0,29
m=0,46
equiaxed to lamellar
lamellar to equiaxed
-6 -4 -2 0 2 4 6 8 10 12
distance from transition [mm]
Fig. 2: Variation of Kop with the change in microstructure
Derived from dislocation theory, equation 1 is valid to calculate Kop in the case of
roughness induced crack closure.
2
1/
2 3/
2 Sθ
K op = C ⋅σ
ys ⋅ K max ⋅ SH
⋅ sin Sθ
⋅ cos
(eq. 1)
2
SH, Sθ: standard deviation of height- and angle-distribution C: fitting parameter
Calculation of Kop is in good agreement with experimental values in lamellar
microstructures showing roughness induced crack closure. In the range of microstructural
transition the calculated Kop values do not fit the experimental ones. This indicates that
small volume fractions of equiaxed grains reduce the roughness induced crack closure
significantly by reducing the shear displacement of the crack tip.
- 64 -

Constrained Sintering of Ceramic Films
Olivier Guillon, Jürgen Rödel
Ceramic coatings are deposited on substrates because of their mechanical properties
(resistance against wear, hardness…), chemical inertness (acting as a protection against
corrosion), low thermal conductivity (thermal barriers coatings for metallic parts in
turbines), electrical, piezoelectrical properties... (functional layers used in multilayer
electronic circuits, sensors, actuators applications). Typical coating thicknesses range from
less than 1 µm to several hundreds of µm. A common way to process such layers is to
disperse ceramic powder in a liquid media. This suspension is then deposited for instance
by dip coating or tape casting. To achieve optimal final properties and adhesion onto the
substrate, ceramic films have to be densified through a heating process (sintering step).
Due to the geometrical constraining conditions imposed by the underlying stiff substrate,
film densification is significantly limited when compared to the free sintering case. As
shrinkage is not allowed in the plane, densification can only take place along film thickness
direction and biaxial tensile stresses arise in plane. These stresses are concentrated by
defects (microcracks which appeared during drying, heterogeneous regions, inclusions...)
and can lead through creep crack growth to consequent damage (cracking, delamination)
in the film.
Sintering behaviour of alumina films has been recently investigated in the Ceramics
Group. A fine and pure α-alumina powder was chosen as a model material for the solid
state sintering. Thanks to a high resolution laser dilatometer and an amplifying mechanical
system, both developed in Darmstadt, it was possible to measure in-situ film shrinkage as
a function of time for different temperatures (from 1150 to 1350°C). Even if shrinkage is
enhanced in the thickness direction, global film densification is reduced. An isotropic
model developed in the framework of continuum mechanics can be used with parameters
(densification rate and viscous Poisson’s ratio) determined on bulk specimens freely
sintered. Predictions systematically overestimate the experimental results (Fig. 1), showing
that the assumption that microstructures of constrained film and free sintering body are the
same may not hold.
A cautious investigation of film microstructure reveals a continuous development of
anisotropy in constrained films during sintering. Pores become more anisometric and
orientate along the thickness direction with increasing density. Thanks to image analysis, it
is even possible to quantify this anisotropy. Similar effects, though much more limited, can
be observed for grains (longer normal to the thickness). These new results may explain
the discrepancies between model and experiments.
- 65 -

Relative density
1.00
0.95
0.90
0.85
0.80
0.75
0.70
1300°C
1150°C
Film exp. Film model
Bulk
0.65
0 2000 4000 6000 8000 10000
Isothermal time [s]
Fig 1. Experiment and modelled densification curves for 2 sintering temperatures
The effect of film thickness was also investigated. Thinner layers seem to be more
constrained, as they densify more slowly than thicker ones. Particle rearrangement may be
hindered close to the substrate, which leads to a lower local density than elsewhere in the
film (Fig 2).
Fig. 2 Polished cross-section of a sintered film
Finally, an extension of the sintering model to anisotropic bodies has been proposed. In
the case of transverse isotropy, 2 free sintering strain rates, 2 uniaxial viscosity as well as
3 viscous Poisson’s ratios are introduced. In specific cases, such as constrained sintering,
only 2 Poisson’s ratios are required. The experimental determination of these parameters
is still challenging, as anisotropic specimens have to be obtained before being loaded in
different directions and their strains measured.
- 66 -

Breakdown-induced light emission and poling dynamics of
porous fluoropolymers
S. Zhukov and H. von Seggern
Recently, a new class of plastics with a very strong piezoelectricity has been discussed in
literature: foams. It has been demonstrated that inner pores, when properly charged in an
external electric field, are responsible for a high piezoelectric response of cellular
polypropylene (PP) [1-3] and expanded polytetrafluoroethylene (ePTFE) [3-5] films.
Surprisingly, a strong difference in the obtainable polarization and the related piezoelectric
d33 coefficients has been recognized between samples with closed-pore (PP) and openpore
(ePTFE) geometry. Most research groups report quasi-static or low-frequency
dynamic coefficients up to 200 pC/N on standard grades of porous PP films, whereas the
open-porous ePTFE films reveal rather small values of 10 to 20 pC/N.
Up to date the charging mechanism of open-porous electrets materials is not completely
understood. To clarify this issue, we investigated the emission of light during the corona
poling of single ePTFE films and the same film sandwiched between two solid FEP films.
Generally, the charging mechanism is supposed to arise from electrical breakdown within
the voids during the poling process [4,5]. The separation of charges due to the electrical
breakdown leads to the aspired polarization buildup. However, each breakdown event is
accompanied by light emission. Thus the emission of light can be considered as a direct
proof of the occurrence of breakdown events and indicates an ongoing poling process
within the sample.
Experiments were carried
12.5 µm FEP
ePTFE
5µm 12.5 µm FEP
out on porous ePTFE films
from GoodFellow
Cambridge Limited,
England. The samples are
63 µm thick with a nominal
porosity of 91% and a pore
size of 1 µm. In order to
handle the films they are
mounted in a circular
aluminum holder with an
inner diameter of 42 mm. A
gold electrode was
deposited onto the bottom
side of the film by thermal
evaporation. The utilized sandwiches are fabricated from the same ePTFE film placed
between an unmetallized FEP film (top) and a one-side-metallized FEP film (bottom) as
displayed in Fig. 1. The employed FEP films have a thickness of 12.5 µm and are
purchased from Sheldahl Company, USA.
63µm
Figure 1. Artist view of the threelayer
sandwich sample.
Negative charging is conducted in air with a corona triode consisting of a point-to-plane
corona discharge and a grid between needle and sample. The charging experiments were
carried out with the unmetallized surface of the samples facing the corona needle. The grid
can be vibrated sinusoidally to measure the surface potential VS of the sample by means
of the Kelvin technique. The dc needle voltage (VC) was kept at VC = −8.0 kV, whereas dc
grid voltage (VG) is varied between 0 and −2500 V to achieve different surface potentials.
In order to measure the light emission during sample poling a photomultiplier (Hamamatsu
R6094) was incorporated into the charging chamber.
- 67 -

Fig. 2 shows the time dependencies for the charging currents IC (a), surface potentials VS
(b) and the light intensities ∆Ilight (c) for a single ePTFE film at grid voltages ranging from
−500 to −1500 V. As soon as the applied electric field exceeds a threshold value of -700 V
the film starts to emit light. The light emission is accompanied by a charging current IC and
a buildup of surface potential VS. After 5 s the current IC, the surface potential VS and the
light emission ∆Ilight saturate to non-zero values. The constant current can be explained by
an equivalent circuit model consisting of the sample capacitor and a leakage resistor in
parallel. The leakage current (saturated current IC) is caused by charge transport initiated
by ongoing local breakdowns. Hence, the charge carriers generated in the material voids
must permanently vanish during the poling process, most likely due to ejection at the metal
electrode and neutralization of corona induced charges at the ePTFE top surface. As a
consequence, the surface charge potential does not change for grid voltages VG < −700 V
[4].
I C , [µA]
V S , [ V ]
∆I light , [a.u.]
0,00
-0,05
-0,10
-0,15
-0,20
-800
-600
-400
-200
0
2,0
1,5
1,0
0,5
0,0
a)
0 5 10 15 20
b) -700... -1500V
0 5 10 15 20
c)
0 5 10 15 20
t 1
-500V
-700V
-800V
-900V
-1000V
-1250V
-1500V
-500V
-1500V
-1250V
-1000V
-900V
-800V
-700V
-500V
time, [sec]
Figure 2. Time dependencies of charging currents (a),
surface potentials (b) and light intensities (c)
during negative poling of an individual ePTFE film
at different grid voltages as indicated.
I C , [µΑ]
V S , [ V ]
∆I light , [a.u.]
0,00
-0,05
-0,10
-0,15
-2000
-1000
0
3
2
1
0
a)
0 25 50 75
b)
0 25 50 75
t 1
c)
0 25 50 75
time, [sec]
Figure 3. Time dependencies of charging currents (a),
surface potentials (b) and light intensities (c)
during negative poling of three-layer sandwich at
grid voltage of -2500 V.
In the contrary to the results obtained from single ePFTE films, the light intensity ∆Ilight and
the charging current IC detected during the poling of the sandwich structure exhibit initially
maxima and decay with time to zero. This is depicted in Fig. 3. Time t1 indicates the onset
of light emission. Concomitantly, the saturated surface potential coincides for all applied
grid voltage with VG. Due to the blocking character of the FEP films, on can anticipate that
the positive and negative charges generated during breakdown are trapped at opposite
- 68 -

ePFTE/FEP film interfaces and cannot leave the ePFTE film. The buildup of oppositely
charged surfaces results in a polarization field compensating for the electric field induced
by the corona charging. Once the internal electric field falls below the threshold field for
electrical breakdown, further electrical breakdown is inhibited and the light intensity as well
as the charging current diminished to zero. The macroscopic dipole formation accounts
also for the drastic difference in piezoactivity between the single porous films and
sandwiched structures. Opposite to the low piezoactivity of the single ePTFE film
(20 pC/N), the three-layer sandwich reveals a large quasi-static piezoelectric d33 coefficient
up to 800 pC/N [5].
In summary, it has been shown that the monitoring of light emission during poling of
porous electrets give an important additional information on the charging mechanism. The
emitted light itself is a direct proof of breakdown in the porous material, which was indeed
observed for the single as well as the sandwiched porous structures. The good agreement
of the poling current and the light intensity progression in time disclose basic features of
the charge separation process in ePTFE layers.
The authors acknowledge the financial support of Arbeitsgemeinschaft industrieller
Forschungsvereinigungen (AiF) “Otto von Guericke” e.V. (ref. Nr.: 09518/03)
References
[1] G. M. Sessler and J. Hillenbrand, Appl. Phys. Lett. 75 (1999) 3405.
[2] J. Peltonen, M. Paajanen, and J. Lekkala, J. Appl. Phys. 88 (2000) 4787.
[3] R. Gerhard-Multhaupt, IEEE Trans. Dielectr. Electr. Insul. 9 (2002) 850.
[4] Z. Hu and H. von Seggern, J. Appl. Phys. 98 (2005) 014108.
[5] Z. Hu and H. von Seggern, J. Appl. Phys. 99 (2006) 024102.
- 69 -

Dielectric interface trap engineering by UV irradiation: A novel
method to control OFET charge carrier transport properties
N. Benson, M. Schidleja, C. Melzer, H. von Seggern
For modern day electronics the integration of field effect transistors with complementary
polarity on a single substrate is essential, in order to enhance the logic capability of the
respective circuits. When considering organic electronics, however, this has proven
difficult since most organic semiconductors exhibit either suitable hole (p) or electron (n)
conduction [1]. The development of organic circuitry therefore requires the deposition of
spatially separated p- and n-type organic semiconductors. However, recent publications
[2,3] revealed the importance of the dielectric/semiconductor interface for charge carrier
Drain
Ca
V DS
Pentacene
PMMA
SiO2 ++ p - Si
Gate
Fig. 1: OFET configuration of both p- and n-type
devices.
Ca
Source
transport in the OFET channel, and
demonstrated the feasibility to
determine the OFET charge carrier
transport properties by controlling the
interfacial electrical trap density.
In the current article we demonstrate
that unipolar p- and n-type OFETs can
be realized by employing pentacene
as the organic semiconductor and a
Ca source/drain metallization. The
OFETs simply differ by UV exposure of
the utilized PMMA dielectric layer in
ambient atmosphere prior to the
pentacene deposition. The OFET
substrate is a highly p-doped
1.7x1.7 cm 2 silicon waver, functioning as the gate contact, with a 200 nm thick SiO2 dry
oxide. In the following, an 120 nm thick PMMA dielectric layer was spin coated from a
2% wt THF solution. Subsequently, the PMMA layer of selected substrates was exposed
to UV light for 10 minutes in air, using
wavelengths of 254 and 185 nm with a
respective intensity of 15 mW/cm 2 and
1.5 mW/cm 2 . A 50 nm thick pentacene
layer and 100 nm thick Ca
Drain/Source contacts were then
precipitated by physical vapour
deposition, using a rate of 2 Å/s at a
chamber base pressure

I D [10 -5 A]
14
12
10
8
6
4
2
0
-2
-4
-6
-8
-10
-12
Before Cycle 1
After Cycle 8
V GS = -80V
0 20 40
VDS [V]
60 80
-80 -60 -40 -20 0 20 40 60 80
with a low current hysteresis
and a steep increase in the
linear region of the transistor,
indicating ohmic contacts for
electron injection. In contrast, an
OFET built on a UV modified
PMMA dielectric exhibits initially
negligible hole and no electron
currents, as illustrated by the
output characteristic shown in
Fig. 3. However, once the OFET
is further operated in electron
accumulation, as shown by the
first quadrant of Fig. 3 at
VGS = 0 V, a significant increase
in ID between the initial and the
8 th operating cycle is visible.
This increase in ID, is due to a
quasi ambipolar hole current [6]
for │VDS│≥│VGS -Vth,p│. The
unipolar p-type characteristic of
this transistor can be confirmed when considering the third quadrant of Fig. 3, showing the
output characteristic measured at VGS = -80 V after the 8 th cycle in hole accumulation.
Surprisingly, the increase in ID occurs despite an energy difference of 2.2eV between the
work function of Ca (2.87eV) and the highest occupied molecular orbital of pentacene
(5.07eV). The pronounced S-shaped output characteristic in the linear region of the OFET
(Fig. 3) indicates the expected large contact resistance.
1/2 [10 -3 A 1/2 ]
I D
12
10
V DS [V]
8
6
4
2
0
V GS = 0V
Individual
Cycles
Linear
regression
Fig. 3: OFET ID characteristic for a UV-modified device. The
first quadrant illustrates ID at VGS = 0 V and the third
quadrant at VGS = 80 V. The arrows indicate the increase in
ID. Inset: ∆Vth during operation in el. accumulation.
The inset of Fig. 3 reveals the origin of the hole current enhancement during subsequent
electron accumulation cycles. Let us first consider the ambipolar drain current equation as
derived by Schmechel et. al. [6] for µn = 0 cm 2 V -1 s -1 and VGS = 0 V:
∆V th
wCeff
µ p
= (VDS
+ Vth,
p − ∆V
) for:│VDS│≥│VGS -Vth,p│. (1)
2l
ID th
Ceff = 10.4 nFcm -2 represents the resulting area capacitance of the SiO2 / PMMA dielectric
layer. With Eq.1 it becomes apparent that the output characteristics in the inset of Fig. 3
are subject to a positive threshold voltage shift (∆Vth), while the hole mobility remains
approximately constant. After the 8 th cycle ∆Vth saturates and reaches approximately 60 V.
This value has been derived from the output characteristic in hole accumulation. We
propose that ∆Vth is a result of trapped negative charge (nt), since it has been
demonstrated that the exposure of PMMA to UV light in air results in the formation of -
COH as well as -COOH functional end groups [4] in the near surface layer of the polymer.
In accordance with the work of Chua et. al. [5], who have recently identified -OH groups as
electron traps, the UV treatment of the PMMA dielectric therefore generates electron traps
at the semiconductor / polymer dielectric interface. Once driven in electron accumulation,
the electron current is inhibited, since the accumulated electrons are trapped. However, as
long as the trapped negative charges are residual, even under hole accumulation, they will
be compensated by positive charges (p) leading to a positive ∆Vth. To obtain a threshold
shift of ∆Vth = 60 V, p can be estimated to be:
- 71 -

∆V
C
q
th eff
12 −2
p ( VGS
= 0V)
= = 3.
9 * 10 cm , (2)
where q is the elementary charge. This figure is equal to nt, as long as the negative
charges are trapped directly at the dielectric/semiconductor interface. The lack in
hysteresis, however, observed for the p-type OFET drain current characteristic, indicates
(1) the absence of hole traps and (2) the absence of recombination of the mobile holes
with the trapped electrons. This leads to the conclusion, that the negative charges are not
localized directly at the semiconductor dielectric interface, but in a near surface layer of the
PMMA dielectric, isolated from mobile holes in the transistor channel.
We have demonstrated the feasibility to convert unipolar n-type pentacene OFETs into ptype
OFETs by a modification of the polymer dielectric through a UV treatment in air. The
change in OFET polarity is due to a large positive threshold voltage shift of about 60 V,
resulting from trapped negative charge carriers within the UV-treated PMMA layer. The
proposed modification of the dielectric / semiconductor interface allows for the
development of organic complementary circuits, since the introduced p- and n-channel
transistors exhibit comparable current characteristics in terms of mobilities (≈ 0,1 cm 2 /Vs),
on / off ratios (≈ 10 4 -10 5 ) and current maxima, as derived from the respective transfer
characteristics.
References
[1] C. D. Dimitrakopoulos and P. R. L. Malenfant, Adv. Mater.14 (2002) 99.
[2] M. Ahles, R. Schmechel, and H. v. Seggern, Appl. Phys. Lett. 85 (2004) 4499.
[3] T. Yasuda, T. Goto, K.Fujita, and T. Tsutui, Appl. Phys. Lett. 85 (2004) 2098.
[4] A. Torikai, M. Ohno, and K. Fueki, J. Appl. Polym. Sci. 41 (1990) 1023.
[5] L.-L. Chua, J. Zaumseil, J.-F. Chang, E. C.-W. Ou, P. K.-H. Ho, H. Sirringhaus, and R.
H. Friend, Nature 434 (2005) 194.
[6] R. Schmechel, M. Ahles, and H. v. Seggern, J. Appl. Phys. 98 (2005) 084511.
- 72 -

Synchrotron Induced Photoelectron Spectroscopy at the Solid-
Liquid Interface of Dye Sensitized Solar Cells
Konrad Schwanitz, Eric Mankel, Ralf Hunger, Thomas Mayer,
and Wolfram Jaegermann
At BESSY we run the experimental station SoLiAS, dedicated to solid-liquid interface
analysis. SoLiAS allows for the transfer of wet chemically prepared surfaces to the ultra
high vacuum without contact to ambient air. In addition in situ (co)adsorption of volatile
solvent species onto liquid nitrogen cooled samples is possible. SoLiAS proves to be very
useful in analyzing the chemical and electronic structure of solid-liquid interfaces e.g. of
dye sensitized solar cells. A monolayer of Ru(N3)-dye was adsorbed from ethanol solution
under clean N2 atmosphere in an UHV-integrated electrochemical cell (EC). Acetonitrile or
benzene were adsorbed from the liquid in the EC or in situ from the gas phase. Ex situ
sintered nanocrystalline anatase substrates as well as in situ deposited polycrystalline
TiO2 samples were used. Distinct reversible changes occur in synchrotron induced
photoelectron valence band and core level spectra when the solvent is adsorbed to
pristine and dye covered TiO2 substrates. Based on the experimental results the alignment
of electronic states and a model on the dye-solvent interaction have been deduced.
The valence band maximum of nc-TiO2 is found at EB = 3.6 eV binding energy while the
fundamental gap is 3.2 eV only. Surface gap states related to Ti 3+ 3d 1 orbitals are found
with a maximum at EB = 1.3 eV and in addition just below the Fermi level. In the rigid band
model these states are assigned to occupied conduction band states but may be due to
substochiometric TiO2-x. Adsorption of acetonitrile is accompanied by quenching of the
surface gap states (Fig. 1). This finding is confirmed in Ti2p core orbital spectra by the
quenching of the Ti 3+ low binding energy shoulder of the Ti 4+ bulk emission. Coadsorption
of acetonitrile (Fig. 2) shifts the dye HOMO by 150 meV from 2.0 eV binding energy to
2.15 eV.
Fig. 1: Intensity normalized (O2p valence
band) SXPS spectra of the gap states of
nanocrystalline anatase TiO2 in the course of
acetonitrile adsorption and desorption.
Fig. 2: SXPS spectra of the gap states of
nanocrystalline anatase TiO2 in the course of
Ru(N3)-dye adsorption and acetonitrile
coadsorption and desorption.
- 73 -

Fig. 3: Schematic of the photovoltaic-relevant
valence states in the rigid band model a) as
prepared nanocrystalline TiO2 anatase film, b) after
dye adsorption from ethanol solution with HOMO
position, c) after coadsorption of the solvent
acetonitrile with the HOMO shifted by 150meV to
higher EB. Using the optical absorption maximum
the LUMO is found 0.17 eV above the Fermi level.
A schematic representation of the
photovoltaic-relevant valence states
as deduced in the simple rigid band
model is displayed in Fig.3. The
measured HOMO corresponds to the
position of the lowest energy holestate
created by the photoemission of
an electron i.e. the HOMO of the
molecular cation. Except for a Franck
Condon shift of approximately 0.1 eV
away from the Fermi level due to
vibrational excitation in the
photoemission process, this is the
relevant energy position for
rereduction by the redox system. For
the electron injection process the
alignment of the LUMO to the
conduction band edge is crucial.
Using the energy of the optical
absorption maximum (535nm =
2.32eV), the LUMO is found 0.17 eV
above the Fermi level.
While the shape of the S2p line of the dye NCS group does not change when benzene is
coadsorbed (Fig 4a right), the S2p emission counterintuitively sharpens upon CH3CN
coadsorption (Fig 4a left). In a simple model (Fig. 4b left) the polar solvent acetonitrile
penetrates the dye layer and the interaction of the dye NCS groups with the TiO2 surface
and with neighbouring dye molecules is suppressed due to a solvation shell. The S2p
intensity development in the course of CH3CN adsorption suggests reorientation of the dye
molecules pointing the NCS groups away from the surface towards the electrolyte. On the
other hand nonpolar benzene just covers the dye layer (Fig. 4b right). The solvation and
orientation of the dye by acetonitrile may be important for obtaining vectorial photovoltaic
charge transfer of the electron from the dye LUMO to the TiO2 conduction band and the
hole from the dye HOMO to the electrolyte.
Fig. 4a: Ru(N3)-dye S2p level in the course of
acetonitrile (left) and benzene (right) coadsorption
and desorption.
- 74 -
Fig. 4b: Cartoon of the Ru(N3)-dye/solvent
interaction in the course of acetonitrile (left)
and benzene (right) coadsorption.

Alkyl- and aryl-modified Si(111) for silicon/organic hybrid devices
Ralf Hunger, Wolfram Jaegermann
Silicon/Organic junctions attract interest in several application perspectives: for
silicon/organic hybrid devices such as biosensors, storage devices, or solar cells, as well
as in the perspective of molecular electronics. It combines the advantages of modularity
and tailoring capabilities of organic chemistry with the established, industrial-scale proven
silicon technology.
An example silicon/organic hybrid device is shown in Figure 1. It is a “wet” field-effect
transistor (w-FET) acting as a biochemical sensor. The central idea of this device is that
biochemical sensor molecules with highly specific binding properties are attached on the
gate electrode of a w-FET. This is the active region of the electrochemical sensor, which
is contacted by an electrolyte. Realizing this device in silicon technology requires two
technological preconditions: a) The gate electrode surface needs to be stable against the
electrolyte (corrosion resistance). b) sensor molecules need to be fixed to the gate
electrode in a defined way, and (lateral) spatial pattern, thus “chemical lithography” is
required.
Fig. 1:
Schematics of an
electrochemical,
“wet” field effect
transistor, w-FET,
for biosensing
applications.
Alkyl-modified silicon surfaces are one interesting class of materials considered for surface
passivation and structuring. Various surface terminations such as methyl-, ethyl, or butylfunctionalized
Si(111) were realized by our collaborator groups at CalTech, Pasadena
(N.S. Lewis), the Waseda University Tokyo (T. Osaka) or at the HMI Berlin (J. Rappich),
employing wet chemical as well as electrochemical processing. A schematic
representation of these surfaces is shown in Figure 3. The methyl-terminated surface is
particular in comparison to the other, longer-chain alkyl-terminations in two aspects: (1)
The methyl (-CH3) termination is the only alkyl species the van-der-Waals radius of which
is small enough such that the passivation of every silicon surface atom by a methyl group
is possible. Our measurements showed that already for the next largest alkyl, i.e. ethyl
(C2H5), only a fractional coverage of about 2/3 of a monolayer are achieved. (2) Methylmodified
n-Si(111) surfaces in the presence of water affect a p-conductive surface
channel, which makes them particularly promising for the implementation as passivation
layers in w-FET devices. The mechanism leading to p-type surface channels is not yet
understood and is a focal point of our studies.
The chemical, electronic, and structural properties of alkylated Si(111) surfaces are
analysed in our “Solid/Liquid Analysis System” (SoLiAS) at the 3 rd generation synchrotron
facility BESSY II in Berlin. SoLiAS is equipped with the analytical methods of highresolution
photoelectron spectroscopy and low energy electron diffraction (LEED). Figure
2 shows the LEED pattern of ethylated Si(111) which proofs an exceptionally high degree
of lateral ordering of the wet chemically processed surfaces. These surfaces are
subjected to further processing steps within the SoLiAS station such as vacuum thin film
deposition, electrodeposition or gas phase adsorption, etc. which allow for an in-situ
- 75 -

synthesis and analysis of interfaces with different contact phases.
The undulator beamline U49/2-PGM2 operated by
our “Collaborating Research Group” BTU Cottbus-
HMI-TU Darmstadt, supplies photon energies in
the range from 90 eV to 1400 eV, and thus core
level emissions as well as valence electronic
structures can be studied in high resolution as
illustrated in Figure 3. Photoelectron spectra of
differently modified silicon surfaces in the valence
band and the C 1s core level regions are shown.
The direct bonding of the terminator group to
surface Si atoms is evidenced by the characteristic emission from the Si-C bond orbital (or
analogously the Si-H bond) at around 5 eV. Another characteristic feature of direct Si-C
linkage (in contrast to carboxylic bonding Si-O-C) is the low binding energy component CSi
at around 284.3 eV (silicon-bound carbon) in the C 1s emission. The second component
CCH2 at 285.0 eV is related to C-C or C-H bonded, aliphatic species. With increasing alkyl
chain length the intensity of the aliphatic component increases. For ethylated Si(111), the
ratio CCH2 / CSi is about 1:1, for butylated Si 1:3 in accordance with expectations. As
mentioned above, based on a careful intensity study, the CH3 termination appears as the
only one to achieve 100 % surface termination.
Fig. 2: LEED pattern of Si(111)-C2H5
In addition to alkylated surfaces, aryl-functionalizations of Si(111) by for example
nitrobenzene or bromobenzene were studied. These systems are interesting for surface
engineering because it could be shown that the molecular dipoles grafted onto the Si(111)
surface affect a surface dipole layer which modifies the silicon surface potential. In our
ongoing research project, the interface engineering possibilities of such alkyl-or arylmodified
surfaces in contact with electrolytes and organic or inorganic semiconductors will
be further investigated.
C1s
hn = 650 eV
C x H y
C CH2
C Si
288 287 286 285 284 283
binding energy (eV)
Butyl-Si
Ethyl-Si
Methyl-Si
H-Si
hn = 150 eV
C 2s
σ Si-C
σ Si-H
20 15 10 5 0
binding energy (eV)
Figure 3: Photoelectron spectra of various alkylated Si(111) surfaces. The direct Si-C linkage is
evidenced by the the surface state emission from the Si-C bond orbital and the low BE component
in the C 1s emission (“CSi”), which is associated with silicon-bound aliphatic carbon. “CCH2”
corresponds to aliphatic, only C-C and C-H coordinated carbon.
- 76 -

New unconventional superconductors:
Water intercalated NaxCoO2
Yoshiharu Krockenberger, Jose Kurian, Philipp Komissinskiy, Lambert Alff
The observation of superconductivity in the layered transition metal oxide NaxCoO2 · y H2O
(K. Takada et al., Nature (London) 422, 53 (2003)) has caused a tremendous upsurge of
scientific interest due to its similarities and its differences to the copper based hightemperature
superconductors. Two years after the discovery, we report the fabrication of
single-phase superconducting epitaxial thin films of Na0.3CoO2 ·1.3 D2O grown by pulsed
laser deposition technique. This opens additional roads for experimental research
exploring the superconducting state and the phase diagram of this unconventional
material.
Superconductivity in NaxCoO2 · y H2O is a property of the cobalt oxide planes. Like in the
case of the cuprates, the phase diagram of sodium cobaltate encompasses several
competing electronic phases, and there are many indications that the superconducting
state is unconventional. While in high-temperature superconductors the twodimensional
character of the corresponding copper oxide planes is stabilized by the intrinsically
strongly anisotropic crystal structure, in NaxCoO2 a complicated water intercalation
process is needed to amplify this anisotropy and induce superconductivity. The main
difficulties in fabricating highquality bulk material of NaxCoO2 · y H2O are the following:
First, sodium can be inhomogeneously distributed in the entire bulk sample, resulting in an
ill-defined doping level. Second, impurity Co oxides such as CoO and Co3O4 are likely to
grow due to the high volatility of sodium. Third, it is difficult to avoid the formation of
Na2CO3 in conventional bulk sample fabrication. As a result, high-quality single crystals or
bulk samples of NaxCoO2 · y H2O are rare, and it is even more difficult to obtain clean
surfaces for optical spectroscopy and tunneling experiments in this material. While highquality
thin films of high-temperature superconductors have allowed a large variety of
phase-sensitive experiments to explore the symmetry of the superconducting order
parameter, corresponding studies have thus far not proven possible for water-intercalated
sodium cobaltate, due to the lack of superconducting thin films. Thin-film deposition
techniques offer major advantages in the synthesis of highquality samples, such as a welldefined
vacuum and oxidizing environment. Recently, epitaxial growth of high-quality, “dry”
NaxCoO2 films by pulsed laser deposition on SrTiO3 substrates has been reported. In
these thin films, phase purity was established within the detection limits of x-ray diffraction
in four-circle geometry, and flat surfaces are obtained. As a further milestone, we now
report the fabrication of superconducting thin films of NaxCoO2 · y D2O.
- 77 -
Fig. 1: White light interferometric scan image
of the surface of a Na0.3CoO2 ·1.3 D2O thin
film on SrTiO3 (001). Within the blue regions
the surface roughness is below 10 nm. The
rare spikes arise from sodium carbonate. [1].

Fig. 2: Resistivity vs temperature for an
epitaxial Na0.3CoO2 ·1.3 D2O thin film on
SrTiO3 (001). In the inset superconducting
quantum interference device (SQUID)
magnetization measurement shows
unambiguously the flux expulsion effect at the
critical temperature of about 4.2 K [1].
For obtaining a film at the desired composition x = 0.3, it is vital to provide a strong
oxidizing agent to deintercalate Na + ions. In principle, this can be accomplished by the
standard Br2–CH3CN-solution method, which is also used for bulk synthesis. However, we
have found that NO2–BF4 is superior to the conventional method, as Br is avoided and the
deintercalation time scale is considerably accelerated. The decisive step is the
intercalation of water into the thin films. In contrast to bulk materials, single-phase thin
films cannot be simply immersed into water, because the thin films tend to peel off the
substrate. Only a much milder method allows the successful fabrication of
superconducting thin films. Oxygen flow with 100% humidity supplied by a D2O bath at a
well-defined temperature (19 °C) is provided to the sample over several days (196 h). In
contrast to alternative preparation routes, this method also yields a clean and smooth
surface (see Fig. 1), which is a necessary prerequisite for meaningful surface-sensitive
measurements. The water-intercalated NaxCoO2 ·y D2O thin films indeed show
superconductivity for x = 0.3 and y = 1.3 with TC,zero about 4.2 K (see Fig. 2). The relatively
sharp superconducting transition with a width of 1.5 K in the resistivity vs temperature
curve confirms the high quality of the thin films. Above the critical temperature, the thin
films show metallic behavior up to room temperature with almost linear slope, similar to the
high-temperature superconductors.
The achievement of superconducting thin films of NaxCoO2 · y D2O paves the way for
additional experiments with this unconventional superconductor. Thin-film-based
Josephson and tunneling experiments, which are expected to yield important clues to the
unconventional nature of superconductivity in this material, can now readily be performed.
Further, superconducting quantum interference device (SQUID) experiments now come
within reach. Such experiments could confirm that, following the discovery of p-wave
superconductivity in Sr2RuO4, the compound NaxCoO2 · y H2O is another metallic solidstate
analog to liquid 3 He with an even higher transition temperature. Following the
successful example of high-temperature superconductors, high quality superconducting
thin film samples of waterintercalated sodium cobaltate thus promise to enhance our
knowledge about this complex material.
In collaboration with MPI Stuttgart (B. Keimer, H.-U. Habermeier, G. Cristiani) and TU
Braunschweig (P. Lemmens)
[1] Y. Krockenberger, I. Fritsch, G. Cristiani, H.-U. Habermeier, Li Yu, C. Bernhard, B.
Keimer, and L. Alff Appl. Phys. Lett. 88, 162501 (2006).
- 78 -

Designed materials for spin electronics
Lambert Alff, Yoshiharu Krockenberger, Andreas Winkler
In the search for new spintronic materials with high spin polarization at room temperature,
we have synthesized an osmium-based double perovskite with a Curie temperature of 725
K. Our combined experimental results confirm the existence of a sizable induced magnetic
moment at the Os site, supported by band-structure calculations, in agreement with a
proposed kinetic-energy-driven mechanism of ferrimagnetism in these compounds. The
intriguing property of Sr2CrOsO6 is that it is at the end point of a metal-insulator transition
due to 5d band filling and at the same time ferrimagnetism and high-spin polarization are
preserved.
A so-called half-metal is a highly desired material for spintronics, as only charge carriers
having one of the two possible polarization states contribute to conduction. In the class of
ferrimagnetic double perovskites such half-metals are well known, e.g., Sr2FeMoO6. The
compound Sr2CrOsO6 described here is special, as it has a completely filled 5d t2g
minority-spin orbital, while the majority-spin channel is still gapped. It is thus at the end
point of an ideally fully spin-polarized metal-insulator transition. At the metallic side of this
transition we have the half-metallic materials Sr2CrWO6 and Sr2CrReO6. Within the unique
materials class of double perovskites, therefore, one can find high-Curie-temperature
ferrimagnets with spinpolarized conductivity ranging over several orders of magnitude from
ferrimagnetic metallic to ferrimagnetic insulating tunable by electron doping. Note that
Sr2CrOsO6, where a regular spin-polarized 5d band is shifted below the Fermi level, is
fundamentally different from a diluted magnetic semiconductor, where spin-polarized
charge carriers derive from impurity states.
While for simple perovskites such as the half-metallic ferromagnetic manganites the Curie
temperature TC is in the highest case still close to room temperature, half-metallic
ferrimagnetic double perovskites can have a considerably higher TC. It has been
suggested that ferrimagnetism in the double perovskites is kinetic energy driven. In short,
due to the hybridization of the exchange-split 3d orbitals of Fe 3+ (3d 5 , majority-spin orbitals
fully occupied) or Cr 3+ (3d 3 , only t2g are fully occupied) and the nonmagnetic 4d/5d orbitals
of Mo, W, Re, or Os (N sites), a kinetic energy gain is only possible for the minority-spin
carriers. This will lead to a corresponding shift of the bare energy levels at the
nonmagnetic site and a strong tendency to half-metallic behavior. This mechanism is
operative for the Fe 3+ and Cr 3+ (M sites) compounds, where all 3d majority-spin states and
all t2g majority-spin states, respectively, are fully occupied and represent localized spins. In
agreement with band-structure calculations this mechanism is naturally associated with
half-metallic behavior, as the spin-polarized conduction electrons mediate
antiferromagnetic order between M and N ions and, thus, ferromagnetic order between the
M sites. In addition, this mechanism will lead to an induced magnetic moment at the
nonmagnetic sites as Mo, W, Re, or Os, in convincing quantitative agreement with recent
band-structure calculations. It has been suggested and verified by observation of the
corresponding x-ray magnetic circular dichroism (XMCD) that the induced magnetic
moment at the nonmagnetic site scales with TC of the compound or, in other words, the
bandwidth in the conducting minority-spin channel scales with the magnetic transition
temperature. This behaviour has also been confirmed qualitatively by nuclear magnetic
resonance (NMR) experiments for FeRe-based double perovskites. Quantitatively,
however, Re shows an unusually enhanced induced magnetic moment in the double
perovskite structure, as compared to Mo, W, and Os.
- 79 -

Fig. 2: X-ray appearance near-edge
structure (XANES) (left axis) and XMCD
signal (right axis) at the Os L2 and L3
edges in Sr2CrOsO6. The inset shows
the element-resolved magnetic
moments of Cr (µCr) and Os (µOs), the
total magnetic moment (µtot), and the
lattice distortion as determined from
neutron scattering data refinement [1].
Fig. 1: Rietveld refinements of the
neutron powder data of Sr2CrOsO6
taken at 553 K. The observed and
calculated diffraction intensities as
well as the difference pattern are
shown. The upper left inset shows a
view along the [111) direction
revealing the rhombohedral structure
of the double perovskite. The upper
right inset shows the temperature
dependence of the Sr2CrOsO6 (444)
diffraction peak (cubic) splitting into a
(404) and (0 0 12) peak (hexagonal).
The XMCD measurements on the
Os L2,3 edges were performed at
the European Synchrotron Radiation
Facility (ESRF) at beamline ID12. As
shown in Fig. 2 a very clear XMCD
signal is observed, signaling a
strong local magnetic moment at the
Os site opposite to the net magnetization. The experimentally determined value is in good
agreement with the neutron scattering result.
We have unambiguously demonstrated that an increase of the number of 5d electrons
leads to an increase of the transition temperature in ferrimagnetic double perovskites
irrespective of the changes in conductivity. Fully spin-polarized conductivity, as indicated
by the large induced magnetic moments and supported further by band-structure
calculations, can be changed from half-metallic behaviour (known in Sr2CrWO6 and
Sr2CrReO6) to insulating behaviour in the high-Curie-temperature ferrimagnetic insulator
Sr2CrOsO6.
In collaboration with MPI Stuttgart (K. Mogare, M. Jansen, M. Reehuis), KTH Stockholm
(A. Delin, G. Vaitheeswaran), and ESRF Grenoble (F. Wilhelm, A. Rogalev). Support by
DFG (AL 560/4).
[1] Y. Krockenberger, K. Mogare, M. Reehuis, M. Tovar, M. Jansen, G. Vaitheeswaran, V.
Kanchana, F. Bultmark, A. Delin, F. Wilhelm, A. Rogalev, A. Winkler, and L. Alff, Phys.
Rev B 75, 020404(R) (2007).
- 80 -

SiCN/C-Ceramic Composite as Anode Material for
Lithium Ion Batteries
Robert Kolb, Claudia Fasel, Verena Liebau-Kunzmann, Ralf Riedel
The choice of electrode and electrolyte materials to design lithium batteries is limited due
to the chemical reactivity of the used materials during the intercalation/deintercalation
process. Amorphous silicon carbonitride ceramics (SiCN) are known to be chemically
stable in corrosive environments and exhibit disordered carbonaceous regions making it
potentially suitable to protect graphite from exfoliation. The material studied in this work
was synthesized by mixing commercial graphite powder with the crosslinked polysilazane
VL20 ® . Pyrolysis of the polymer/graphite compound at appropriate temperatures in inert
argon atmosphere resulted in the formation of an amorphous SiCN/graphite composite
material. First electrochemical investigations of pure SiCN and of the SiCN/C composite
are presented here. A reversible capacity of 474 mAhg -1 was achieved with a sample
containing 25 wt% VL20® and 75 wt% graphite. The measured capacity exceeds that of
the used graphite powder by a factor of 1.3 without any fading over 50 cycles.
Potential [V] vs. Li/Li +
3,5
3,0
2,5
2,0
1,5
1,0
0,5
0,0
450°C
650°C
850°C
1050°C
1250°C
Graphite
0 100 200 300 400 500 600 700
Capacity [mAhg -1 ]
Fig. 1: First charge- and discharge of 25VL20-75C samples pyrolysed at different temperatures
compared to pure graphite vs. Li/Li + .
- 81 -

Capacity [mAhg -1 ]
700
600
500
400
25VL20-75C charge
25VL20-75C discharge
pure Graphite charge
pure Graphite discharge
300
0 10 20 30 40 50
Cycle number
Fig. 2: Change of capacity after the first 50 cycles of 25VL20-75C powder sample pyrolysed at
1050 °C compared to pure graphite powder vs. Li/Li + .
Conclusion and Outlook
This finding indicates that the SiCN phase is an active phase in terms of lithium
intercalation/deintercalation and that it is a promising candidate as protective layer on
graphite, due to its chemical stability. Still unfavourable is the low coulombic efficiency due
to the large specific surface area of the formed SiCN phase. Therefore future work will be
focused on reducing the surface area to improve the electrochemical properties.
Furthermore the influence of the amorphous SiCN layer on the capacity and chemical
stability of other electrode materials like silicon and optimized carbon materials as well as
on different electrolytes is of particular interest.
- 82 -

Recent Advances in New Hard High-Pressure Nitrides
Andreas Zerr 1 , Ralf Riedel 1 , Toshimori Sekine 2 , J. E. Lowther 3 , Wai-Yim
Ching 4 , Isao Tanaka 5
1 Institut für Materialwissenschaft, TU Darmstadt, Petersenstr. 23, 64287 Darmstadt, Germany
2 Advanced Materials Laboratory, National Institute for Materials Science, Tsukuba 305-0044, Japan
3 DST-NRF Center of Excellence in Strong Materials and School of Physics, University of the Witwatersrand,
P. O. Wits, 2050, Johannesburg, South Africa.
4 Department of Physics, University of Missouri-Kansas City, Kansas City, Missouri, 64110, USA
5 Department of Materials Science and Engineering, Kyoto University, Yoshida, Sakyo, Kyoto 606-8501
Japan.
Since the discovery of spinel nitrides in 1999, there is presently much effort in basic
science to further develop advanced nitrides and electronic nitrides. Aim and scope of the
research in this field is to synthesize novel nitrides for structural and functional
applications. Silicon-based spinel nitrides combine ultra-high hardness with high thermal
stability in terms of decomposition in different environments and are expected to show
interesting optoelectronic properties. These features make spinel nitrides suitable for
applications as cutting tools and light emitting diodes, respectively. The ultra-high pressure
and temperature synthesis of spinel silicon nitride and germanium nitride on the one hand
as well as the successful synthesis of tin nitride at ambient pressure on the other hand
have caused an enormous impact on both basic science and technological development of
advanced nitrides. Moreover, the novel phases of transition metal nitrides like Zr3N4 and
Hf3N4 with Th3P4 structure as well as the recently published mono nitrides of Pt or Mo
demonstrate the scientific potential of high pressure synthesis techniques in the field of
materials science. Here, the state of the art and the progress in the field of novel hard
materials based on nitrides and produced under high pressure are reviewed.
Fig. 1: Spinel-type structure of γ-Si3N4 (left) with calculated electronic band structure (right).
- 83 -

Texture investigations and field emission properties
of metallic nanowires
Florian Maurer, Joachim Brötz, and Hartmut Fueß
Due to their quasi one-dimensional geometry metallic nanowires possess high aspect
ratios, i.e. high ratio of length over diameter. High nanowire aspect ratios, as well as small
radii of curvature of the nanowire tips lead to an amplification of an externally applied
electric field [1] and thus increases the probability of a field emission current by tunnelling.
For field emission applications of vertically-aligned metallic nanowire ensembles it is
desirable to control the aspect ratio, as well as the radius of curvature. A suitable method
to fabricate high aspect nanowire ensembles (diameter a few ten nm, length a few ten µm)
with controllable geometric and structural properties is the polymer template technique [2]:
Nanoporous templates are produced by irradiating polymeric foils with accelerated heavy
ions. After chemical etching of the ion-induced damage tracks, the cylindrical pores of the
template are filled with metal by electrodeposition. The nanowire diameter is adjusted by
the time of etching the ion-induced tracks and its height is controlled during
electrodeposition by coulometry. The radius of curvature, i.e. the degree of single
crystallinity can be controlled by different electrodeposition parameters, e.g. temperature
or overvoltage. Different preferred growth orientations, i.e. textures, of the nanowires might
influence the field emission properties of metallic nanowires in terms of work function. Fig.
1 shows a scanning electron microscopy (SEM) image of a copper nanowire ensemble.
Fig. 1: SEM image of an ensemble with free-standing and vertically-aligned copper nanowires.
Strong textures in direction have been observed for numerous metallic fcc
nanowires under direct current (dc) deposition conditions [2, 3]. On the other hand, a
preferred growth direction of fcc nanowires in has been observed under alternating
current (ac) deposition conditions [3]. X-ray diffractograms of Au nanowire ensembles of
different textures are shown in Fig. 2.
- 84 -

intensity I [a.u.]
intensity I [a.u.]
a)
111
200
200
220
220
311
30 40 50 60 70 80 90 100 110 120
b)
111
texture
311
texture
30 40 50 60 70 80 90 100 110 120
222
222
diffraction angle 2θ [°]
400
400
331 420
331 420
Fig. 2: X-ray diffractograms of Au nanowire ensembles of a) texture under ac deposition;
b) texture under dc deposition conditions; the dashed vertical lines with triangles atop
represent the intensity distribution of a polycrystalline and untextured sample.
To explain these experimental results, the broken bond model [4] is applied to the
anisotropy of single-crystalline or textured wires in combination with surface-energy
minimization growth tendencies: The energy of an atomic surface is considered to be
proportional to its broken-bond density. The constitution of the circular top and base
planes, as well as the cylindrical mantle surfaces depend on of the wire and can be
determined from crystallographic projections [5]. The evolution of the surface energy E
of textured fcc nanowires with increasing aspect ratio h/d, is shown in Fig. 3.
Up to an aspect ratio of 1 a texture represents the configuration of lowest energy.
At higher aspect ratios the orientation becomes the most favourable growth
direction. In TEM investigations for such oriented Au nanowires with strong textured large
elongated grains were observed. Under ac conditions, lattice sites of high reactivity, i.e.,
lattice defects or surfaces with high number of broken bonds are preferentially dissolved
during the anodic cycles of the alternating polarity. As {110} surfaces exhibit a high
number of broken bonds these lattice sites, and thus the texture, successively
disappear under ac conditions. In absence of {110} surfaces, a texture represents
the orientation of lowest energy for aspect ratios larger than~5 (see Fig. 3). In TEM
investigations a distinct texture in direction was only observed at the upper part of
the nanowires, i.e. the texture starts to develop at an advanced state of the
electrodeposition. X-Ray line profile analysis can be used to show that surface defects are
preferably dissolved compared to line defects (dislocations) und ac conditions. The
texture under dc and the texture under ac deposition conditions become stronger at
smaller diameters, as the transition aspect ratios are reached earlier.
Field emission properties of nanowire ensembles can be investigated in terms of field
emission scanning microscopy. Emitter densities of 4.4×10 4 cm -2 and 2.4×10 4 cm -2 were
determined for bare and Au-coated Cu nanowire ensembles of 10 6 cm -2 , respectively.
Emission of only a few percent of the nanowires was ascribed to mutual electrostatic
- 85 -

screening effects. Gold coating of copper nanowires influences field emission in terms of
higher radii of curvature and work function. The mean emitted currents were about 50 nA
for bare and µA for Au coated single nanowires. A mean field amplification factor of
245 was deduced from the slope of a Fowler-Nordheim plot of bare Cu nanowires [6]. In
general, Au coating improves stability of field emission. Furthermore, Cu nanowire
ensembles were successfully tested as cryogenic electron sources in Penning traps for
high sensitive measurements of the g-factor of charged particles. Requirements in the
electron source is a stable field emission current of a few ten nA at low temperatures (5 K),
high magnetic fields and under high vacuum (up to 10 -16 mbar). The field emission
properties of nickel nanowire ensembles were improved by Au coating, where a lower field
amplification factor of 302 was observed for Au coated compared to 331 for uncoated Ni
nanowires [7].
total surface energy E
(normalized to γ {111} )
0.36
1.00
aspect ratio (h/d)
5.00
Fig. 3: Evolution of surface energy E of textured fcc nanowires with aspect ratio h/d.
[1] T. Utsumi; IEEE Transactions on Electron Devices 38 (1991) 2276
[2] M.E. Toimil-Molares, J. Brötz, V. Buschmann, D. Dobrev, R. Neumann, R. Scholz,
I.U. Schuchert, C. Trautmann, J. Vetter; Nucl. Instr. Meth. Phys. Res. B 185 (2001)
192.
[3] S. Karim, M.E. Toimil-Molares, F. Maurer, G. Miehe, W. Ensinger, J.
Liu, T.W. Cornelius, R. Neumann; Appl. Phys. A 84 (2006) 403.
[4] J.K. Mackenzie, A.J.W. Moore, J.F. Nicholas; J. Phys. Chem. Solids 23, (1962) 185.
[5] F. Maurer, J. Brötz, S. Karim, M.E. Toimil-Molares, C. Trautmann, H. Fuess;
Nanotechnolgy (2007), 135709.
[6] F. Maurer, A. Dangwal, D. Lysenkov, G. Müller, M.E. Toimil-Molares, C. Trautmann,
J. Brötz, H. Fuess; Nucl. Instr. Meth. Phys. Res. B 245 (2006) 337.
[7] A. Dangwal, G. Müller, F. Maurer, J. Brötz, H. Fuess; J. Vac. Sci. Tech. B (2007) in
press.
- 86 -

Material modifications induced by swift heavy ions in NbTi
Aleksandra Newirkowez 1 , Joachim Brötz 1 , Hartmut Fuess 1 , Reinhard
Neumann 2 , Christina Trautmann 2 , Kay-Obbe Voss 2
1 University of Technology, Darmstadt, Germany; 2 GSI, Darmstadt, Germany
The Facility for Antiproton and Ion Research (FAIR) to be built at GSI will be equipped with
superconducting magnets. Due to the high beam intensities and related beam losses,
radiation damage of the Cu/NbTi superconducting wires used in the magnet coils has to be
considered [1]. Radiation-induced degradation of the superconducting properties of NbTi
alloy was studied in the 1970s and ‘80s. Using projectiles such as protons, neutrons,
deuterons, and O ions, was shown to result in increased electrical resistivity and
decreased critical current, superconducting transition temperature, and upper critical
magnetic field [2]. These irradiations with light and/or low-energy ion beams involve small
electronic energy losses.
Here we are interested in radiation effects in particular in structural changes produced with
swift heavy ions (2.6-GeV U) of much higher electronic energy deposition.
A superconducting wire has typically a diameter of ~1 mm and consists of several
thousand thin NbTi-filaments arranged in bundles embedded in a copper matrix for thermal
stabilization (Fig. 1). The filaments are a few µm thick and are composed of β-NbTi (bcc)
and α-Ti precipitate (hcp) which improve the critical current by flux-pinning. During the
cold-drawing process of the filaments, the β-NbTi matrix develops a
crystallographic texture.
Fig. 1: Optical micrograph of cross-section of multifilamentary wire (dark: NbTi filaments, light: Cu
matrix).
The irradiation of NbTi filaments was performed at the UNILAC (GSI) applying fluences
between 3×10 11 and 5×10 12 ions/cm 2 at a flux of 1 - 2×10 8 ions/cm 2 ·s. Before irradiation,
the copper matrix was dissolved in aq. FeCl3. The filaments were clamped on an Al holder
and exposed to a beam of 2.6-GeV U ions at room temperature. The electronic energy
loss (dE/dx)e for U in NbTi is 53 keV/nm.
Radiation-induced effects were examined using transmission electron microscopy (TEM)
(Philips CM20, 200 keV), x-ray powder diffraction (λMo–Kα1 = 0.70926 Å) in flat-sample
transmission geometry and with four-circle diffractometry (λCo–Kα = 1.78897 Å).
- 87 -

Figure 2 shows a selected region of the diffraction pattern of filaments irradiated with
different fluences. The position of the dominant reflection of β-NbTi remains unchanged,
i.e., there is no obvious change of the lattice parameters. The weak reflection of the
equilibrium hcp α-Ti phase decreases already at a low fluence of 3×10 11 ions/cm 2 . By
TEM, we find evidence for the hexagonal ω-Ti phase probably resulting from a transition of
α- into ω-Ti [3]. Neither track formation nor any other phase transition or amorphization of
the β-NbTi phase was detected.
Fig. 2: X-ray diffraction pattern of filaments as function of applied fluence.
Irradiated filaments showed changes of the β-NbTi texture, but quantitative analysis is
problematic due to the small diameter of the filaments. We therefore measured larger foil
samples with a ( 100)[
110]
texture before and after irradiation at a four-circle
diffractometer. Comparing their pole figures gives evidence of irradiation-induced
degradation and rotation of the azimuthal distribution of the (100) planes (Fig. 3).
Fig. 3: (100) pole figures of NbTi-foil (left: virgin, right: irradiated with 10 12 cm -2 U ions).
References
[1] L. Latysheva, N. Sobolevskiy, G. Moritz, E. Mustafin, G. Walter, GSI Scientific Report
2003 (May 2004) p. 252.
[2] S.T. Sekula, J. Nucl. Mat. 72 (1978) 91.
[3] H. Dammak, A. Dunlop, D. Lesueur, Nucl. Instr. Meth. B 107 (1996) 204.
- 88 -

SIMS Analysis of Carbide Nanofilms of Titanium and Tantalum
Formed by Methane Plasma Immersion Ion Implantation
S. Flege, G. Kraft, W. Ensinger
It is well-known that ion implantation of carbon into reactive carbide-forming metals such
as titanium leads to thin films of hard carbides which improve the tribological resistance of
the metal. Apart from conventional beam-line ion implantation, plasma immersion ion
implantation (PIII) can be used.
Titanium and tantalum samples were treated by high voltage pulses at -20 kV in an
atmosphere of methane. The high voltage created a plasma, from which ions of methane
and its fragments were accelerated towards the sample and were implanted. Process
times between 0.5 and 2 hours at a pulse repetition rate of 1 kHz were used.
The samples were analyzed for phase composition by glancing incidence X-ray diffraction
(GIXRD). The element composition was analyzed by X-ray photoelectron spectrometry
(XPS) and by secondary ion mass spectrometry (SIMS) with 8 kV O2+ sputtering.
Fig. 1 shows the SIMS depth profile, given as mass signal intensities over the sputtering
time, of a Ti sample, treated for 1h. 6 masses have been recorded: H-1, C-12, O-16, Ti-46,
Ti-48, and Ti-48 C-12 (mass 60).
Fig. 1: SIMS element profile of Ti, treated by
pulse biasing for 1 h
- 89 -
Fig. 2: SIMS carbon profiles of Ti samples,
treated for 0.5, 1, or 2 h, extracted from the
C-12 signals

The spectrum shows that apart from C, hydrogen has been implanted. In the plasma,
different hydrogen-containing ionic species are present, such as CH4 + , CH3 + , and
CH2 + . The H profile starts at a certain level at the surface, and drops almost an order
of magnitude in depth. The carbon profiles of samples, treated with different process
times, are compared in Fig. 2. They were extracted from the C-12 signal. A strict
quantitative comparison is not possible, as the secondary ion yield might slightly
differ, however, one can state that the amount of incorporated carbon increases with
process time. Also, the shape of the depth profiles change. At the lowest process
time, the profile drops monotonely with depth.
A process time of 1 h leads to a typical PIII implantation profile: a slight drop below
the surface, followed by an increase, and a slope down to the background level.
When the process time is doubled, the profile changes further. A plateau seems to be
formed, indicating a possible saturation effect. The situation with tantalum is similar.
Fig. 3 shows the depth profile of five masses, apart from the above mentioned H, C,
and O, it is Ta-181, and Ta-181 C-12. Again, a typical PIII implantation profile is
observed.
Fig. 3: SIMS element
profile of Ta, treated
by pulse biasing for 2
h
The carbon profiles are compared in Fig. 4. An increase in process time leads to an
increase in the amount of implanted C. It can be assumed that the carbide film is
shallower in comparison to Ti. The thickness of the carbide zone is dependent on
mass and density of the sample element, because the projected range of the carbon
ions is a direct function of substrate mass and density. For a full acceleration voltage
of 20 kV and CH4 + ions, the energy of the C atom is 15 keV, while it is 1.25 for each
H atom, as the molecule breaks up upon impact and the single atoms take a part of
the kinetic energy of the molecule, according to their mass. Following SRIM
calculations, the projected range of 15 keV carbon ions in Ti is 32.5 nm, while it is
only 14.6 nm in Ta. Other species, such as CH2 + show accordingly a slightly higher
energy. However, a part of the ions have a lower kinetic energy, as they do not
experience the full acceleration voltage or they collide with molecules from the gas
atmosphere. The sum of all energies, as well as sputtering effects, lead to the
observed depth profiles.
- 90 -

In the XRD spectra, apart from the peaks of Ti and Ta, small peaks of the respective
carbide phases MeC can be identified. Carbon implantation led to formation of the
carbide phase. The peaks are rather weak and broad, which is assumed to be a
consequence of small grain sizes and the shallowness of the implanted zone. XPS
combined with Ar sputtering showed the development of the binding conditions with
depth. In the C1s spectrum, on top of the sample, a thin film of elemental carbon was
found. After 1 min sputtering, a chemical shift to carbide was detected. With
increasing sputtering time, i.e. depth, the C signal became smaller and vanished,
when the thickness of the implant region was exceeded. The Ti2p signal appeared at
the position of the carbide and shifted to the position of elemental Ti upon sputtering.
This showed that the TiC phase had been formed, in accordance with XRD.
Basically, the same result was found for Ta in the C1s and Ta4f spectra.
Fig. 4: SIMS
carbon profiles of
Ti samples,
treated for 0.5, 1,
or 2 h, extracted
from the Ta-181
C-12 signals
It can be
concluded that pulse biasing titanium and tantalum in an atmosphere of methane in
an appropriate pressure range leads to formation of a methane plasma from which
ions are accelerated towards the metal targets. Thus, thin gradient films of implanted
carbon are formed. Carbide phase formation has been shown by X-ray diffraction,
indicating the presence of small carbide crystallites, and by the shifted photoelectron
energy states of metal and carbon. Depth profiling by sputter etching in combination
with photoelectron spectroscopy and by secondary ion mass spectrometry showed
thin carbon films on top and gradient carbide films below.
Acknowledgments
The authors would like to thank Deutsche Forschungsgemeinschaft (DFG) for
financial support with the project EN207/19-1.
The fruitful collaboration with Drs. K. Baba and R. Hatada from Industrial Technology
Center of Nagasaki is gratefully acknowledged.
- 91 -

The effect of crystallinity on the thermal instability
of gold nanowires
S. Karim, W. Ensinger
Metallic nanowires are an important component of future nanoscale devices. Among
other important factors, the thermal stability of nanowires is crucial for a reliable
performance of nanowire based devices. Recent experimental and theoretical results
demonstrate that the so-called Rayleigh instability causes the decay of a cylindrical
nanowire into nanospheres in particular at elevated temperatures where atomic
movement by diffusion becomes significant. This pose a serious obstacle to the
sustained reliability of nanowire based devices. For this reason, the Rayleigh
instability of gold nanowires was investigated. The emphasis was on their
crystallographic properties.
Cylindrical gold nanowires with diameters D = 87 nm were prepared by
electrochemical deposition in Polycarbonate templates. The polymer foils of
thickness 30 µm were irradiated normal to the surface at the UNILAC linear
accelerator of GSI, Darmstadt, with uranium ions of energy 2 GeV at a fluence 10 8
ions/cm 2 . Nanoporous templates were then produced by chemically etching the latent
ion tracks. After deposition of a conductive Cu back-electrode, wires were grown
electrochemically in the templates. By systematically varying the deposition
conditions, polycrystalline (PC) and single-crystalline (SC) gold nanowires with wellcontrolled
crystallographic characteristics were obtained. Characterization of wires by
X-ray diffraction (XRD), and transmission electron microscopy (TEM) confirmed that
the SC gold wires contained no grain boundaries and possess a strong 〈110〉
preferred orientation. The PC wires exhibit a bamboo-like structure with the grain
sizes varying between several hundred nanometers and few micrometers . Figure 1
shows representative XRD diffractograms of both types of samples.
Intensity (a.u.)
111
Cu
200
Cu
220
311
222
40 60 80 100
2 Theta (deg)
Fig. 1: XRD patterns of (a) single-crystalline and (b) poly-crystalline wires of diameter 87 nm.
Cu reflections are ascribed to the Cu back-electrode.
For the annealing experiments, the Polycarbonate matrix was dissolved. The
samples were introduced in a vacuum furnace (~5×10 -4 Pa), heated up to a
temperature
- 92 -
Cu
(a)
(b)

Ta = 600 o C, held at Ta for a certain annealing time ta, and then cooled down to room
temperature. The samples were examined using a high-resolution scanning electron
microscope (HRSEM). The micrographs in Figure 2 illustrate two sequences of the
morphological transformation of (left) poly- and (right) single-crystalline cylindrical
gold wires caused by the Rayleigh instability. For both type of wires thickness
undulations are first developed along the wire axis leading to fragmentation.
Eventually, the fragments change to spheres. Figures 2a and 2e display the
morphology of the as-prepared poly- and single-crystalline wires prior to annealing.
The polycrystalline wires developed axial perturbations after one hour annealing (Fig.
2b), and the wires fragmented, and decayed partially into nanospheres after ta = 2 h
(Fig. 2c). Finally after ta = 2.5 h, the wires had been transformed completely into
chains of nanospheres (Fig. 2d). The decay of the single-crystalline wires is depicted
in Figures 2e-2h. The single-crystalline wires proved to be significantly more resistant
to Rayleigh instability compared to the polycrystalline ones. First radial perturbations
appeared after ta = 2.5 h, fragmentation was observed after ta = 3 h, and complete
decay into spheres occurred only after an annealing time of ta = 5 h.
200nm RT
(a)
(b)
(c)
(d)
2µm
5µm
2µm
500nm
t a =1h
t a =2h
t a =2.5h
200nm
(e)
200nm
(f)
RT
2µm t a =3.5h
(g)
(h)
5µm
t a =2.5h
t a =5h
Fig. 2: The HRSEM images show the stages of the decay of poly- (left), and single-crystalline
(right) gold nanowires of diameter 87 nm into nanospheres upon annealing for different times
ta at 600 o C.
In summary, the results that the nanowire crystallinity influences the Rayleigh
instability considerably. The single crystalline wires are found to be more resistant
against the Rayleigh instability than polycrystalline ones of the same thickness.
Acknowledgment:
The authors would like to thank Drs. T.W. Cornelius, R. Neumann (GSI), and A.G.
Balogh (Thin Films) for the fruitful collaboration.
- 93 -

Electrochemical investigation and characterisation
of thin-film porosity
F. Sittner, W. Ensinger
Especially thin film technology has to meet the high demands of the trend of
miniaturization in technical applications. In spite of shrinking dimensions of technical
devices their performance must keep up and even improve. The coatings have to be
homogenous and free from pores to keep their protective properties against wear and
corrosion. Apart from the difficulties of the deposition process itself even the
characterization of the film-porosity is nontrivial, since high resolution imaging
methods like atomic force microscopy or scanning electron microscopy can only
reproduce a small piece of the whole sample’s area. And it is hardly possible to
distinguish between defective spots only located on the surface of the film and pores
that go through the whole coating material giving rise to a corrosive attack on the
substrate. With electrochemical methods small defects in thin insulating films can be
easily detected.
Three different carbon-based coatings were deposited onto polished iron substrates.
Thin fullerene films were deposited via evaporation followed by an ion beam
treatment to crush the fullerene molecules and form a dense amorphous carbon
layer. Another set of samples were coated with poly(p-xylylene), which is a very good
insulating polymer, in a vapour phase deposition process.
The porosity of coated metal samples was analyzed using cyclic voltammetry in a
weakly acidic medium. A sample plot is shown in Fig.1 to illustrate the procedure.
The potential range from -1 to
current density I / Acm
-2
1.0E-01
1.0E-02
1.0E-03
1.0E-04
1.0E-05
1.0E-06
EOC
Icrit.
-1000 -500 0 500 1000
potential E / mV
Fig.1: current density vs. potential plot of an uncoated
iron substrate in an acetate buffer with a pH of 6,75
+1 V was scanned with 10
mV/s and the current density
was recorded. The shape of
the curve gives information
about the corrosion
mechanism and two important
measurands can be extracted
from the current density vs.
potential plot: the maximum
“critical” dissolution current Icrit.
and the open circuit potential
EOCP.
When the potential rises
beyond EOCP the anodic
reaction dominates and the
current density increases
rapidly due to the dissolution of
the iron substrate. The current
density reaches a maximum
which is called the “critical
current density” Icrit. after which the current drops several orders of magnitude. The
drop is due to the sedimentation of corrosion reaction products on the metal surface
– first as a thin porous film, finally as a dense oxide layer, protecting the metal from
further corrosive attack. This state is called “passivation”. The height of Icrit. is
proportional to the size of the uncoated area on the sample surface. This uncoated
- 94 -

area represents the porosity of the protective coating, which now can be easily and
directly measured via the critical current density. EOCP is the open circuit potential,
which varies with different coatings. This is a fact which has attracted only little
attention, so far. Plotting Icrit. against the number of measuring cycles gives an
impression of the long term
current density I crit. / Acm -2
1.0E-01
1.0E-03
1.0E-05
1.0E-07
0 2 4 6 8 10
number of cycles
uncoated iron
fullerene film
plasma-treated
fullerene film
Fig. 2: Icrit. vs. scan cycles for uncoated iron, C60-film
and irradiated C60-film
behaviour of the sample.
This can be seen in Fig. 2
which shows the
development of critical
current densities over a
period of 10 cycles for an
uncoated iron sample, a
fullerene coated sample and
a fullerene coated sample
which has been treated with
an argon ion bombardment.
It can be seen that both
coatings reduce the current
densities significantly about
two orders of magnitude but
the long-term behaviour of
the ion-treated sample is
much better. This is due to
ion bombardment which
formed a thin and dense layer of amorphous carbon in the upper region of the
coating, improving the protection abilities of the film.
current density Icrit. / Acm -2
EOCP / mV
-590
-600
-610
-620
-630
1.5E-04
1.0E-04
5.0E-05
0.0E+00
0 50 100 150 200 250
0 50 100 150 200 250
film thickness / nm
Fig. 3: Development of a) EOCP and b) Icrit. with increasing
film thickness for C60-coated iron samples
- 95 -
a
b
Another set of fullerenecoated
samples with different
film thicknesses was
investigated and the change
of Icrit. and EOCP was
recorded. The results are
shown in Fig. 3. With higher
film thickness, current
densities decrease because
existing pores are closed or
narrowed with increasing film
thickness. The development
of EOCP is quite remarkable
because the potential should
not be affected by the film
thickness since
electrochemical potentials
are not dependent on the
surface area which is
determined by the film
porosity.

This phenomenon can be understood considering a pore not as a simple cylindrical
hole, characterized by its base area and height. Actually due to the three-dimensional
shape of a small pore it acts as a diffusion barrier for the dissolved ions. Therefore in
a small pore the near surface concentration of dissolved iron will be higher than in a
wider pore through which the dissolved ions can much easier diffuse away from the
surface. But the higher the iron concentration near the surface is, the more is a
further dissolution inhibited and the necessary potential to continue the dissolution is
shifted to higher anodic values. That means if a metal surface is covered with an
insulating coating a high shift of the open circuit potential into anodic direction
indicates very small pores in the coating material.
This correlation is supported by the results from similar measurements of iron
samples that had been coated with different film thicknesses of the insulating polymer
poly(p-xylylene) as can be seen in Fig. 4. Again there is a shift of the open circuit
potential in anodic direction going along with a decrease in porosity at higher film
thicknesses.
current density I / A cm -2
1.0E-02
1.0E-05
1.0E-08
1.0E-11
1.0E-14
-1000 -500 0 500 1000
Fig. 4: Iron samples coated with poly(p-xylylene)
potential E / mV
140 nm
240 nm
560 nm
While the dissolution current density is proportional to the sum of the base areas of
all pores in the coating, the potential shift of the open circuit potential is an indicator
of the average size of the pores. Thus it is possible to distinguish between a few
major flaws in the coating and a widespread micro-porosity which may both show the
same current density.
- 96 -

Self-consistent theory of unipolar charge-carrier injection
in metal/insulator/metal systems
F. Neumann, Y.A. Genenko, C. Melzer, H. von Seggern
Charge carrier injection is an important factor in many electronic devices, especially
in applications with insulators, where virtually all charge carriers have to be injected
from the electrodes. Examples that have been the subject of interest are electronic
devices built with organic semiconductors such as organic light-emitting diodes
(OLEDs). In this work we develop a device model for a metal/insulator/metal system
including the description of charge carrier injection at both metal/insulator interfaces.
This model takes into account the electrostatic potential generated by the charges
injected. The treatment of this issue faces the problem of self consistency, since the
amount of injected charges depends on the height of the energy barriers at the
contacts, while the electrostatic potential generated by this charge modifies the
height of the injection barrier itself. This problem is solved by defining the boundary
conditions in the electrode materials far away from the contacts, where the influence
of the charge transfer can be ignored. As a result, charge carrier densities and
electric field distributions in the respective media are coupled and depend on the
conditions of the system.
Let us consider an insulator of thickness L sandwiched in between two metal
electrodes. The insulator is supposed to be extended over the space with –L/2 < x <
L/2, whereas the metal electrodes are extended over the semi spaces with x < -L/2
and x > L/2, respectively. The continuity of the electrical displacement and of the
electrochemical potential across the whole system entails, particularly, at the metal/
insulator interface the following boundary conditions:
± ±
⎡ ∆ eε
l
⎤
TF
( ± L / 2)
= N exp⎢−
± F ( ± L / 2)
⎥
⎣ kT kT ⎦
ns s
where (x)
is the electron density in the insulator,
n s
(1)
N is the effective density of
±
states in the LUMO band (LUMO – lowest unoccupied molecular orbital), ∆ are the
energy barriers between the Fermi-levels of the respective metal electrodes and the
±
bottom of the LUMO-band, T is the temperature, lTF
is the Thomas-Fermi length in
the respective electrodes, ε is the dielectric constant of the insulator, Fs (x)
is the
electric field in the insulator, k and e are the Boltzmann constant and the
elementary charge, respectively. Using the above boundary conditions the onedimensional
drift-diffusion equation together with the Poisson equation were solved
numerically.
Knowledge about the distribution of the electric field allows for the determination of
the voltage drop V across the whole system for a given current density j and hence
for the calculation of the current-density-voltage (I-V)-characteristics. In Fig. 1 we
present I-V-characteristics of a Ca/organic/Mg system. The I-V-curve calculated for
vanishing injection barriers represents a limitation of the current flow through the
system. The curves at V>1V with ∆ < ∆ ≅ 0.
27 eV coincide with that in the case
−
crit
- 97 -

∆ = 0
−
exhibiting dominance of space charge effects at low barriers. At low voltages
up to 0.1 V all I-V-characteristics show an Ohmic-like j ≈ V dependence. This Ohmic
regime is followed by an exponential increase of the current density with the voltage
up to the built-in voltage VBI = 0.81 eV corresponding to the difference in the workfunctions
of the electrodes. This increase can be attributed to a diffusive charge
carrier transport against the weakened electric field in the organic material. If a high
injection barrier is present, the following current-density increase is also exponential
due to the barrier modification by the electric field at the interface. After all, when the
injection barrier at the injecting electrode falls below ∆ crit the calcium contact can
supply more charge carriers than the bulk of the organic semiconductor can
transport. That is why all the I-V-characteristics end up in the space charge limited
regime.
In the case of high injection barriers the approximate analytic consideration results in
the I-V-characteristic of the system which reads
⎛ eV ⎞
− exp⎜−
⎟ −1
V + V ⎛ ∆ ⎞
BI
eff
exp⎜
⎟ ⎝ kT
j = −eµ
⎠
s N
⎜
−
⎟
, (2)
L ⎝ kT ⎠ ⎛ e(
V + VBI
) ⎞
exp⎜−
⎟ −1
⎝ kT ⎠
where µ s is the mobility of electrons in the insulator and the modified barrier equals
−
−
∆eff
= ∆ + eε lTFFs
( −L
/ 2)
. The agreement of this formula with numerical calculations is
perfect for reverse and forward bias until the space charge effects become dominant.
Fig. 1: I-V-characteristics for an organic layer with thickness L = 100 nm contacted with a
calcium electrode at x = -L/2 and a magnesium electrode at x = L/2. The injection barrier of
the calcium electrode is varied from 0 eV to 0.4 eV with an increment of 0.1 eV.
Finally, the presented model is capable of describing a metal/insulator/metal device
in the injection limited as well as in the space charge limited regime and reveals
conditions of the crossover from one regime to another.
- 98 -

Penetration of an external magnetic field into a multistrip
superconductor/soft-magnet heterostructure
S.V. Yampolskii, Y.A. Genenko, H. Rauh
Heterostructures made up of superconductor (SC) and soft-magnet (SM)
constituents are being studied extensively because of their potential for improving
the performance of SCs. The use of SMs for such structures offers the possibility
to alter the pinning of magnetic vortices in the SC constituents through easy
tuning of the intrinsic magnetic moment of the SM constituents. Furthermore, the
large permeability of SMs allows to improve the critical parameters of SC wires
and strips by shielding the transport current self-induced magnetic field as well as
an externally imposed magnetic field.
As is known from previous work, the critical current of a periodic structure of SC
strips separated by slits is markedly enhanced compared with that of an isolated
SC strip. Here, therefore, we study how filling the slits with SM strips controls the
penetration of magnetic flux into such a heterostructure. To this end, we consider
a periodic array of infinitely extended type-II SC and SM strips of respective
widths wS and M , i.e. period , and thickness d, oriented parallel to
the x-y-plane of a cartesian coordinate system x, y, z and exposed to a transverse
external magnetic field H , as shown in Fig. 1. The SC constituents shall be
devoid of magnetic flux penetrated from their infinitely far ends; the SM
constituents shall be fully described by the relative magnetic permeability
w w=w S+wM
0
µ .
Assuming, in addition, d/w

constituents. The requirement of vanishing of the z-component of the total
magnetic field on the surfaces z= ± d/2 of the SC constituents,
Hz( x ) =H 0 +HS,z( x ) +HM,z( x)
, determines the sheet current distribution in the
Meissner state.
The field of complete penetration of magnetic flux, H p , corresponds to the
transition of the SC constituents into the full critical state; it is found by setting
H z =0 for x =0 in conjunction with the sheet current distribution
J( x) =-Jcsgn ( x)
which, in turn, is governed by the critical sheet current Jc
.
Fig. 2 displays the calculated dependence of H p on the relative width of the SM
constituents using different values of d and µ .
Fig. 2: Variation of the field of complete penetration of magnetic flux into the SC strips
with the width of the SM constituents, for dw=0.005, µ = 1000 (curve 1), dw=0.01,
µ = 500 (curve 2) and dw=0.01, µ = 1000 (curve 3).
Evidently, due to the presence of even narrow SM strips, H p slightly increases
compared to the respective field p H 0 for the case of a periodic array of isolated SC
strips. A pronounced rise of H p occurs when the width of the SM constituents
grows relative to the width of the SC constituents; behaviour which can be
explained by the fact that, owing to their high permeability, the SM strips attract
part of the external magnetic flux so as to decrease the effective local magnetic
field applied to the SC constituents. This redistribution of the field also occurs in a
periodic array of isolated SM strips, where maximum reduction of the total
magnetic field halfway between the strips, ∆Hz = ( H0d πw) ψ ⎡⎣ ( w -wM) 2 ⎤⎦
with the
digamma function ψ , is attained in the limit µ >> 1.
- 100 -

Structural stability of multiply twinned FePt nanoparticles
Michael Müller and Karsten Albe
The prospect of realizing magnetic nanoparticles that can be applied in high-density
recording or medical applications has driven a large number of research activities in
recent years. Among all candidate materials FePt in the face centered tetragonal L10
phase has attracted much attention. This structure is characterized by alternating Fe
and Pt layers in c-direction and possesses a high uniaxial magneto-crystalline
anisotropy energy (MAE). Because of the high MAE, single crystalline FePt
nanoparticles with a diameter as small as 4 nm can maintain a stable magnetization
direction on a time scale of 10 years. When prepared by gas-phase synthesis
processes, however, no single crystalline FePt particles are obtained. Instead,
multiply twinned shapes in the form of icosahedral or decahedral particles are
predominant. In order to understand the occurrence of the different structural
motives, a detailed knowledge of the energetics of FePt particles in the various
conformations is necessary. In our work we investigated the structural stability of
FePt nanoparticles by atomic scale and continuum model calculations.
In conjunction with a recently developed interatomic FePt potential, the molecular
statics method has been applied for calculating the fully relaxed energy of FePt
nanoparticles in single crystalline, multiply twinned icosahedral and multiply twinned
decahedral morphologies. The particle energy as a function of size is shown in Fig. 1.
In general, even for the smallest particle sizes studied, the single crystalline shapes
are energetically favored over multiply twinned particles by at least 10 meV/atom.
Also, icosahedral particles exhibit a much higher energy than decahedral ones
because of their higher internal strain and larger twin boundary areas. The large
energy differences between single crystalline particles on the one hand and
icosahedral and decahedral particles on the other hand, however, can mainly be
attributed to a large twin boundary energy predicted by the interatomic potential.
Compared to electronic structure calculations, an overestimation of the twin boundary
energy by a factor of two is possible.
Fig. 1: Average potential energy for FePt nanoparticles in different morphologies. Data points
denote molecular statics calculations, curves are predictions of the continuum model Eq. (1).
- 101 -

In order to assess the influence of the uncertainty of the twin boundary energy, a
more versatile continuum description of particle energies has been employed. In this
continuum model, the energy of a nanoparticle is approximated by the sum of
volume, surface and twin boundary energy terms:
E( N)
= N E + W + A ( N)
γ + A ( N)
γ . (1)
( c ) twin twin ∑
hkl hkl
hkl
Here, Ec is the cohesive energy per atom in the bulk phase and W is an average
strain energy per atom, which is zero for single crystalline particles. Atwin and γtwin
denote the twin boundary area and its energy. Furthermore, Ahkl and γhkl denote the
total area and energies of the hkl facets terminating the particle surface. For
validating the continuum model, its predictions on particle energies when provided
with materials parameters from the interatomic potential are compared with the
atomistic calculations in Fig. 1, where an excellent agreement is found.
By varying the surface and twin boundary energies, Eq. (1) has now been used for
evaluating the boundaries between stability domains of decahedral, icosahedral and
single crystalline particles as is shown in Fig. 2.
Fig. 2:.Stability of FePt particles in multiply twinned and single crystalline morphologies as
obtained from Eq. (1) by varying surface and twin boundary energies. The vertical lines
indicate surface and twin boundary energies predicted by the interatomic potential used in
Fig. 1 and values estimated on the basis of first principles calculations.
For estimating which set of surface and twin boundary energies best describes
reality, reference values from first principles calculations have been considered,
which amount to 100 meV/Å 2 and 6.5 meV/Å 2 , respectively. For this set of energies,
Fig. 2 reveals that icosahedral particles are stable up to a diameter of 2.6 nm.
The calculations on particle energies provide a reasonable explanation for the
predominance of icosahedral FePt nanoparticles prepared by inert gas condensation.
Since icosahedral particles are energetically most stable for small sizes below 2.6
nm, it is likely that icosahedral seeds evolve during the nucleation stage of inert gas
condensation. When growing further, kinetic trapping of the particles in the
metastable morphology can then lead to the presence of icosahedral particles even
at larger sizes.
- 102 -

Phase diagram of the Pt-Rh alloy studied with a refined
BOS mixing model
Johan Pohl and Karsten Albe
The Pt-Rh alloy is used in automotive exhaust gas converters as a three-way
catalyst. It has attracted much attention from the scientific community due to its
catalytic applications. But although many studies have been performed on the bulk,
surface and nanoparticulate properties of this alloy, some features still remain
puzzling. An answer to the question whether Pt-Rh phase separates or not could only
recently be given. The widely accepted phase diagram, which shows a miscibility gap
and predicts a critical temperature of 1033K, has been constructed by E. Raub [1] in
1959. He inferred from the experimentally confirmed phase separation in Ir-Pt, Ir-Pd
and Pd-Rh, that Pt-Rh would behave similarly. The critical temperature was
estimated from the difference in the melting points of the two constituents. Although
the phase diagram was reprinted many times since, a miscibility gap has never been
observed in experiment. Recent ab-inito density functional theory (DFT) studies [2], in
contrast, provide strong hints that Pt-Rh does not phase separate, but that various
ordered compounds exist at temperatures below 300K. These studies have been
corroborated by experimental results using diffuse X-ray scattering in order to
measure the amount of short-range order present in the alloy at a temperature as
high as 923K [3]. A corrected phase diagram for Pt-Rh, however, that incorporates
the findings of the last 10 years has not been available so far.
Fig. 1: The phase diagram of Pt-Rh based on our calculations, the 40 and D022 structures are the
stable compounds that are found at low temperatures, above 240K there are no stable ordered
structures.
- 103 -

In this study, we have therefore determined the Pt-Rh phase diagram by calculating
the grand canonical potential. We applied the thermodynamic integration method
using lattice-based Monte Carlo simulations in the semi-grand canonical ensemble,
where the total number of atoms is fixed, while the difference between the number of
A and B type atoms is allowed to fluctuate for a fixed chemical potential. A
numerically efficient lattice based Hamiltonian was developed by fitting an improved
version of DePristo’s bond-order simulation (BOS) mixing model [4] to a set of input
data obtained from DFT calculations. The calculated the phase diagram of Pt-Rh is
shown in Fig. 1. The phase boundaries are obtained by looking for discontinuities in
the order parameter when integrating down over temperature at constant chemical
potential, and for discontinuities in concentration when integrating over the chemical
Fig. 2: The first eight Warren-Cowley short range order parameters in the vicinity of the
order-disorder transition for Pt-50 at.% Rh. The ordered structure below the transition
temperature is “40”.
potential at constant temperature.
The order-disorder transition of both ordered phases were furthermore analyzed by
calculating the Warren-Cowley short range order parameters (see Fig. 2).
The jump in the order parameters occurs at 239 K if we start with an ordered
configuration and is slightly higher if a random distribution is cooled from high
temperatures. The order-disorder transition was also examined for the stable D022
structure at a concentration of 75 % rhodium. In that case we find a transition
temperature of 210K. Just as for the case of the “40” structure the phase transition is
of first order.
[1] E. Raub, J. Less-Common Met 1, 3 (1959)
[2] Z. Lu, B. Klein and A. Zunger, J. Phase Equilib. 16, 36 (1995)
[3] C. Steiner et al., Phys. Rev. B 71, 104204 (2005)
[4] L.Zhu and A. DePristo, J. Chem. Phys. 102, 5342 (1995)
[5] A. Kohan, P. Tepesch, G. Ceder and C. Wolverton, Comp. Mat. Sci. 9, 389 (1998)
- 104 -

Pt-Ru fuel cell catalysts subjected to H2, CO, N2 and air
atmosphere: An X-ray absorption study
C. Roth, V. Croze, J. Melke 1 , M. Mazurek, F. Scheiba
1 Fraunhofer Institut für Solare Energiesysteme (ISE), Freiburg
Nanoscale metal particles continue to attract interest because of their unique
properties and their importance as catalytically active materials in heterogeneous
catalysis. In particular, binary and multinary systems have been in the focus of recent
research, as the combination of different metals results in fascinating synergistic
effects. A prominent example for bimetallic systems applied in fuel cells is Pt-Ru,
where Ru is added to Pt to enhance its CO tolerance, when used with COcontaminated
fuels [1]. Essentially, two mechanisms have been proposed for the
improved CO tolerance: 1) a bifunctional mechanism [2], where oxygen-containing
species are produced at the Ru sites, which oxidize strongly-adsorbed CO from
neighboured Pt sites, and 2) in a so-called ligand effect with ruthenium modifying the
electronic structure of the Pt by donating electron density, thus either weakening the
Pt-CO bond and thereby allowing CO to be more easily oxidized by OH adsorbed at
the Pt surface, or by enhancing Pt-H2O activation and thereby allowing the reaction
of OH and CO directly on the Pt [3]. Which mechanism dominates in operation, is
largely determined by the samples morphology and the Pt/Ru site distribution, as
revealed in recent literature [4, and references therein].
The structure of different Pt-Ru electrocatalysts has been investigated in dependence
of the prevailing atmosphere using a new reactor/furnace set-up, which enables Xray
absorption spectroscopy (EXAFS) measurements in transmission geometry,
whilst the catalysts are heated up to 100 °C in 5% H2/N2, 5% CO/N2, N2, and air
atmosphere. EXAFS is especially suited for the characterization of nanoscale
supported catalysts, as no long-range order is required and there is no need for ultrahigh
vacuum conditions. In contrast to recent literature describing in-situ experiments
at commercial catalysts in operating fuel cells and reporting mostly metallic Pt and Ru
during operation [3], we specifically decided to exclude the influence of
electrochemical potential. By this, it should be possible to distinguish between effects
brought about by potential and those induced by atmosphere and temperature,
although it has to be borne in mind that the electrolyte and the potential have a huge
effect on the chemistry. It is assumed, that catalyst changes will be exaggerated in
the gas phase, as both the electrolyte and water double layer are supposed to
reduce these effects significantly.
Two different monometallic (Pt/C, Ru/C) and two different bimetallic (Pt-Ru/C alloy,
Pt/Ru/C mixture) electrocatalysts were investigated in different atmospheres at a
temperature of 100 °C in the in-situ XAS reactor. Figure 1 shows the proposed
structural models calculated by conventional EXAFS analysis.
- 105 -

Fig. 1: Proposed models for a) Pt, b) Pt-Ru alloy, and c) Pt/Ru mix samples. Black atoms
indicate Ru(O)x, green atoms indicate Ru, yellow atoms indicate Pt.
The model for the Pt-Ru alloy sample is composed of 80 atoms, 40 Pt and 40 Ru,
with approximately 1/3 of the Ru atoms present as Ru(O)x islands. The sample is not
pictured as well-alloyed, but almost as a fusion of Pt and Ru nanoparticles with a
relatively small Pt-Ru interface. The Pt/Ru mixture, however, is calculated to be an
amalgam of Pt nanoparticles (50 atoms) with a small (3 atoms) surface Ru
substituent, coincident with similar Ru nanoparticles (40 atoms) with a parallel Pt
surface constituency (8 atoms). Obviously, as the coordination numbers predicted by
the EXAFS fit are an average per metal atom, and as the mechanical mixing method
is unlikely to produce identical individual nanoparticles, it is not suggested that this
model indicates the absolute configuration of the sample.
norm. absorption [a.u.]
1.5
1.0
0.5
0.0
11.54 11.56 11.58 11.6 11.62
photon energy [keV]
FT kχ(k)
0,15
0,10
0,05
0,00
-0,05
-0,10
0 1 2 3
R [Å]
Fig. 2: XANES spectra recorded at the Pt L3 edge in air, H2/N2, and CO/N2 for Pt-Ru (left) and
corresponding Fourier transforms in hydrogen (black, solid line), in CO (gray, solid line) and
in air atmosphere (black, dashed line).
In Figure 2, the XANES region of the spectra recorded for Pt-Ru at the Pt L3 edge in
air, 5 % H2/N2, and 5 % CO/N2 is shown. In air as well as in nitrogen atmosphere, all
three catalysts appear significantly oxidized, as indicated by their pronounced whiteline
intensities. This, of course, means that they were already oxidized in their pristine
- 106 -
4

state, and neither air, nor nitrogen atmosphere change this situation. Upon exposure
to either CO or hydrogen, however, the white-line decreases significantly. In the case
of the hydrogen, this decrease indicates reduction of the oxides present in the
pristine sample. In CO atmosphere, the modified white-line is assumed to result from
both a reduction of surface oxides present as well as a strong interaction between
the CO and the catalyst surface (CO poisoning). In contrast to both bimetallic
samples, in the monometallic Pt catalyst the decrease in white-line intensity appears
to be less pronounced due to a stronger degree of CO poisoning.
The oscillatory part of the XAFS data changes significantly as a function of the
atmosphere, which can be seen best in the corresponding Fourier transforms (FT’s)
(Fig. 2, right). The FT’s in CO and hydrogen look very similar and metal-like, whereas
the FT in air displays distinctly different features indicative of an oxide. Fitting of the
data has been performed using the XDAP code, and the respective R and N values
are reported elsewhere [5]. The XANES and EXAFS results support each other nicely
indicating the reduction of platinum oxides by hydrogen, whereas CO adsorbs
strongly at Pt surfaces in all three catalyst systems. Ruthenium oxides become
reduced easily in hydrogen, while the reduction of ruthenium oxides in CO
atmosphere seems to depend on the Pt and Ru surface site distribution.
In summary, alloy formation seems to be advantageous, as it decreases particle
growth and oxidation in the catalysts. Evidence of CO poisoning has been observed
on all Pt surfaces, but most pronouncedly for the pure Pt catalyst. Moreover,
significant differences between Pt-Ru alloy and Pt/Ru mixture have been revealed,
and are due to the different Pt/Ru site distribution. A clear effect of Ru island
morphology on O and CO adsorption, as described in the literature [4], has been
observed: the larger Pt-decorated Ru nanoparticles of the mixture are significantly
more oxidized than the Ru surfaces in the alloy. A significant amount of Pt/Ru
neighbour sites is required, as Pt “catalyzes” the reduction of nearby ruthenium
oxides. Furthermore, Ru-CO bonds are strengthened via the ligand effect also
depending on the Pt/Ru site distribution. The observed differences should also lead
to mechanistic differences in real fuel cell operation.
Financial support of the DFG has been gratefully acknowledged. The authors thank
F. Haass, M. Bron, H. Fuess and P. Claus for providing the in-situ furnace set-up and
E. Welter and the staff at beamline X1, Hasylab, Hamburg, for their kind support.
Literature
1. H. A. Gasteiger, N. M. Markovic, P. N. Ross, Jr., E. J. Cairns, J. Phys. Chem.
98, 1994, 617.
2. T. Yajima, H. Uchida, M. Watanabe, J. Phys. Chem. B 108, 2004, 2654.
3. C. Roth, N. Benker, T. Buhrmester, M. Mazurek, M. Loster, H. Fuess, D. C.
Koningsberger, D. E. Ramaker, J. Am. Chem. Soc. 127, 2005, 14607.
4. F. J. Scott, S. Mukerjee, D. E. Ramaker, submitted to J. Electrochem. Soc.
5. C. Roth, N. Benker, M. Mazurek, F. Scheiba, H. Fuess, Appl. Catalysis A 319
(2007) 81-90.
- 107 -

Synthesis of oxide-polymer nanocomposites via plasma
polymerization
Jens Suffner (1) , Gallus Schechner (2) , Hermann Sieger (1) , Horst Hahn (1),(3)
(1) Joint Research Laboratory Nanomaterials
(2) SusTech GmbH
(3) Institute for Nanotechnology (FZ Karlsruhe)
In the last years, nanoscale materials have gained tremendous interest in science
due to their unique properties, like superparamagnetism, superplasticity, and
quantum confinement.
Nanoscale powders are characterized by a large surface-to-volume ratio leading to
specific surface areas in the range of several hundreds of square meters per gram.
Therefore it is obvious, that the particle-matrix interface has a large impact on the
properties of the particles. In this work [1] , the oxide nanoparticles silica and zirconia
have been produced by thermal decomposition in a hot wall reactor followed by a
subsequent coating with a polymer (see figure 1).
Fig. 1: Setup for the in-situ production of polymer coated oxide nanoparticles.
Plasma polymerization is a feasible technique for the production of dense coatings
on particles. Schallehn et al. [2] have been able to produce plasma polymerized
ethylene (ppE) by this technique. Here, we describe the formation of various
polymers on silica and zirconia and study the influence of the monomer on the
resulting surface properties. A large variety of substances can be used as starting
material for the organic coating, what allows tailoring of the interface properties and
adopting the surface properties to the matrix medium by the right choice of monomer,
e.g. siloxanes for silicone matrices. The following monomers could be successfully
coated on the oxide core:
• Hexafluoro-m-xylene (C8H4F6) and hexafluoropropene (C3F6), leading to highly
fluorinated surfaces
• Octamethylcyclotetrasiloxane (C8H24S4O4), leading to a siloxane surface
• Methylmethacrylate (MMA, C5H8O2) and ethyl-2-cyanoacrylate (ECA,
C6H7O2N), leading to an acrylate surface
- 108 -

Figure 2 shows the successful coating of plasma polymerized hexafluoro-m-xylene
on ZrO2. Polymerization through plasma agitation always leads to an amorphous
coating that can be clearly distinguished from the dark and crystalline oxide core. In
all cases, oxide particles can be produced with diameters smaller than 10 nm and
varying coating thickness of 2 - 10 nm.
Fig. 2: Transmission electron micrograph of
an amorphous polymer coating on the zirconia
core (Image by R. Schierholz, Structural
research division).
Transmittance T [a.u.]
3180
ν (N-H)
ν (C-H)
ppECA/
SiO (p)
2
CO
2
ppMMA/
SiO 2
SiO 2
1600
ν
1710
(C=C)
ν (-C=O)
δ (C-H)
880
δ (Si(CH 3 ) 2 )
3000 2000 1000
Wavenumber [cm -1 ]
*
*
*
* SiO 2
*
*
*
664
δ (N-H 2 )
Fig. 3: FT-IR spectra of uncoated silica, silica
coated with plasma polymerized MMA
(ppMMA/SiO2) and silica coated with plasma
polymerized ECA (ppECA/SiO2).
The influence of the coating material on the dispersability was studied in the case of
the acrylate-based coatings ppMMA and ppECA on silica [3] . Powders derived from
methylmethacrylate are characterised by a hydrophobic surface, making it impossible
to disperse them in water. The powders are not wettable. The exchange of a methyl
group to a cyano group (-CN) in the monomer leads to enhanced dispersability in
water. In the plasma, the C≡N bond is split and reassembled with hydrogen in the
coating to form –NH2 groups, as determined by FT-IR spectroscopy (Fig. 3). The
hydrocarbon bands of the coating can be found in the range of 2875 – 2960 cm -1 .
Vibrations of the methacrylate can be identified around 1710 cm -1 for the C=O bond
and around 1600 cm -1 for the double bonded carbon. The vibrations responsible for
δ(N-H2) around 664 cm -1 and for ν(N-H) around 3180 cm -1 appear only in the
spectrum measured on particles coated with ECA-derived coatings.
Literatur:
[1] J. Suffner, Diploma thesis, Faculty of Materials- and Geo-Sciences (TU
Darmstadt), 2006
[2] M. Schallehn, M. Winterer, T.E. Weidrich, U. Keiderling, H. Hahn, Chem. Vap.
Deposition 2001, 9, 40.
[3] J. Suffner, G. Schechner, H. Sieger, H. Hahn, Chem. Vap. Deposition
(accepted for publication)
- 109 -
*
*
*

Diploma Theses
Böhme, Mario; Herstellung und Charakterisierung von β-FeSi2/Si
Kompositwerkstoffen zur photovoltaischen Applikationen; Surface Science;
December 06
Bohn, Tilman; Vergleich zweier Methoden zur Bestimmung lokaler Umformgrade
verzweigter Blechstrukturen; Physical Metallurgy ; February 06
Braun, Dennis; Injektion von Ladungsträgern in organische Halbleiter; Electronic
Material Properties; September 06
Depner, Udo; Werkstoffeigenschaften von ultrahochfesten Stählen für den Einsatz in
Strukturbauteilen; Physical Metallurgy ; April 06
Elsen, Alexander; Untersuchungen des Einflusses von Versuchsparametern auf die
ermittelten Werkstoffkennwerte aus dem uniaxialen, quasistatischen Zugversuch;
Physical Metallurgy; October 06
Engert, Andrea; Metal to Ceramic Sealant Joints for Planar Solid Oxide Fuel Cells;
Ceramics Group; December 06
Ettinghausen, Frank; Hochfeste duktile eutektische Ti-Legierungen; Physical
Metallurgy ; March 06
Frommherz, Martin; Charakterisierung von hochtemperaturbeständigen Cu/Al2O3
Verbundwerkstoffen mit Durchdringungsgefüge; Ceramics Group; October 06
Gaab, Lotta; Bruchzähigkeit von Perlmutt der Abalone; Ceramics Group; April 06
Gassmann, Andrea; Ursache und Einfluss der Grenzflächenpassivierung auf die
elektrischen Eigenschaften von organischen Feldtransistoren; Electronic Material
Properties ; February 06
Hinterstein, Manuel; The Solution of the (6x5) surface superstructure3D Structural
Determination of C60on Au(110); Structure Research; May 06
Kling, Jens; In-situ elektronenmikroskopische Untersuchung der Domänenstruktur
von Pb(Ti,Zr)O3 unter Polung; Structure Researchructure Research; November 06
König, Markus; Herstellung und Charakterisierung eines Kupfer-Aluminiumoxid-
Verbundwerkstoffs mit Durchdringungsgefüge; Ceramics Group; May 06
Körber, Christoph; Charakterisierung der Halbleiter-Heterogrenzfläche ZnO/GaAs
mittels Photoelektronenspektroskopie; Surface Science; August 06
Kostka, Johannes; Variation der Boranentwicklung in boranatbasierten
Nanokompositen für die Wasserstoffspeicherung; Joint Research Laboratory
Nanomaterialsmaterials ; October 06
Krämer, Urs; Einfluss der Sauerstoff- und Schwefelkonzentration auf die optischen
Eigenschaften von europium-dotierten Cäsiumbromid; Electronic Material Properties;
March 06
Langbein, Falko; Fließverhalten und dessen Berechnung dualer Gefüge der (α + β)-
Titanlegierung Ti-6Al-4V; Physical Metallurgy ; May 06
- 110 -

Lange, Tobias; Organische CMOS-Technik durch Grenzflächenmodifikation;
Electronic Material Properties; October 06
Langer, Jochen; Elektrostatische Dispergierung von Zinkoxid-Pulvern und
Herstellung von Schichten; Ceramics Group; October 06
Leist, Thorsten ; Spannungsunterstütztes Polen von PZT; Ceramics Group;
October 06
Meidel, Bernd; Herstellung wismut- und zinkhaltiger Perowskite; Ceramics Group;
November 06
Molberg, Martin; Lichtinduzierte Streuung in Blei-Lanthan-Zirkonat-Titanat; Ceramics
Group; October 06
Monnoyer, Maxime; Silizium-Farbstoff-Hybridsystemen für die Photovoltaik:
Abscheidung auf p+ dotierten Siliziumfilmen; Materials for Renewable Energies;
October 06
Paturaud, Flora; Mikrostruktur und mechanische Eigenschaften von Kobalt-Eisen-
Legierungen; Physical Metallurgy ; October 06
Pauly, Simon; Charakterisierung eines duktilen Glas-Matrix-Komposits auf Kupfer-
Zirkonium-Basis; Physical Metallurgy ; May 06
Pavlovic, Goran; Abscheidung piezoelektrischer Na0,5K0,5NbO3-Schichten aus
Schlickern auf Ringelektroden, deren Sinterung und Charakterisierung; Ceramics
Group ; March 06
Richter, René; Untersuchungen zum Erstarrungsverhalten von Weichlotlegierungen;
Physical Metallurgy ; May 06
Rudnig, Jan; Untersuchungen und Charakterisierung von Al/Al2O3 und TiMgN PVD-
Beschichtungen auf der Magnesium-Druckgusslegierung AZ91D im Hinblick auf die
Erhöhung der Verschleißbeständigkeit und unter Berücksichtigung des
Korrosionsverhaltens; Physical Metallurgy ; May 06
Sager, Sascha; Herstellung und Charakterisierung metallischer Gläser und
Komposite in den Systemen FeZr und AlYNiCo; Physical Metallurgy ; November 06
Schaab, Silke; Nanostrukturierte Beschichtungen aus Kohlestoff-Nanoröhren/TiO2
Kompositen für funktionelle und bio-medizinische Anwendungen; Ceramics Group;
July 06
Schidleja, Martin; Der Einfluss von Dielektrika auf die Ambipolarität von Transistoren;
Electronic Material Properties; February 06
Schmid, Hanna; Untersuchung des Ladungstransports in organischen Halbleitern
mittels Flugzeitmessungen; Electronic Material Properties ; February 06
Schmidt, Hans; Struktur-Eigenschaftsbeziehungen von weißelektroluminesziereden
Polymeren; Electronic Material Properties ; February 06
Siepchen, Bastian; Modelluntersuchungen an der CdS/CdTe Heterogrenzfläche;
Surface Science; March 06
- 111 -

Sperling, Sebastian; Untersuchungen zur Phasenbildung und Stabilität von Al3Mg2;
Physical Metallurgy ; June 06
Straub, Florian; Pulsed Laser Desposition of Self-Assembled Multiferroic BiFeO3-
CoFe2O4 Thin Film Nanostructures; Ceramics Group; October 06
Suffner, Jens; Funktionalisierung von oxidischen Nanopartikeln durch
Plasmapolymerisation; Joint Research Laboratory Nanomaterialsmaterials ; May 06
Zils, Susanne; Entwicklung eines neuen Verfahrens zur Herstellung von Membran-
Elektroden-Einheiten (MEA) über ionomer-gecoatete Katalysatoren; Materials for
Renewable Energies; September 06
PhD Theses
Balke, Nina; Ermüdung von Pb(Zr,Ti)O3 für unterschiedliche elektrische
Belastungsformen; Ceramics Group; July 06
Dindorf, Christian; Ermüdung und Korrosion nach mechanischer
Oberflächenbehandlung von Leichtmetallen; Physical Metallurgy; April 06
Ensling, David; Photoelektronenspektroskopische Untersuchungen der
elektronischen Struktur dünner Lithiumkobaltoxidschichten; Surface Science;
September 06
Erhart, Paul Harro; Intrinsic Point Defects in Zinc Oxide: Modeling of Structural,
Electronic, Thermodynamic and Kinetic Properties; Materials Modeling; July 06
Klonczynski, Alexander; Herstellung und Charakterisierung hochtemperaturstabiler
Si(B)OC Keramiken auf Basis kommerzieller Polysiloxane; Dispersive Solids;
December 06
Knoth, Markus; Zur Realstruktur von Perlglanzpigmenten; Structure Research;
May 06
Krockenberger, Joshiharu; Epitaxial thin film growth and properties of unconventional
oxide superconductors cuprates and cobaltates; Thin Films; December 06
Mazurek, Marian; Impedanzspektroskopie an Anodenkatalysatoren für
Membranbrennstoffzellen; Structure Research; February 06
Säuberlich, Frank; Oberflächen und Grenzflächen polykristalliner
kathodenzerstäubter Zinkoxid Dünnschichten; Surface Science; July 06
Vollmar, Emanuel; Strukturelle Phasenübergänge und physikalische Eigenschaften
von Zintl-Phasen des NaTl-Strukturtyps; Structure Research; April 06
Weiler, Ulrich; Silizium-Farbstoff-Hybridsysteme für die Photovoltaik - Präparation
und Eigenschaften; Surface Science; February 06
Westram, Ilona; Crack Propagation in Pb(Zr, Ti)O3 under Cyclic Electric Loading;
Ceramics Group; July 06
- 112 -

Mechanical Workshop
The mechanical workshop of the Institute of Materials Science is designing,
manufacturing and modifying academic equipment for a broad range of projects. In
the year 2006 the workshop was involved in the following major projects:
• Design and realisation of a new neutron structure powder diffractometer
(SPODI) at the FRM-II, TU Munich, Garching
• UHV-preparation chambers dedicated for MBE, CVD, PVD and
(electro)chemical treatment
• Design and manufacturing of a protection chamber for x-rays with up to
150keV photons
Staff Members
Head
Jochen Korzer
Technical Personnel Frank Bockhard
Ulrich Füllhardt
Volker Klügl
Herry Wedel
Electronic Personnel
Michael Weber
- 113 -

Institute of Applied
Geosiences
Physical Geology and Global
Cycles
In the solar system, Earth is an unique rocky planet with an ocean and an
atmosphere. It is inhabited by bacteria since about 4 billion years and by higher life -
plants and animals - since ca. 600 million years. Organisms, air, water, and rocks are
interconnected in an unending cycle of matter and energy: The Earth System.
The crustal plates of Earth are driven by radioactive heat. This causes creation of
new crust at mid-ocean ridges at rates of several centimetres per year. On the other
side, plate margins collide, become subducted into the mantle again, or fold up vast
mountain ranges like the Alps and the Himalayas, combining rocks of very different
origin. During subduction the basaltic crust is partially melted generating more felsic
magmas which rise to form continental-type plutons and to cause lines of andesitic
volcanoes such as occurring around the entire Pacific rim. This is called the
endogenic cycle of rocks.
At the same time Earth receives solar radiation which moves air and water in gigantic
cycles around the planet. Specifically the water cycle causes the denudation of
mountains by mechanical erosion and the leveling of plains by chemical weathering,
the latter aided tremendously by vegetation and their CO2-input to soils. This is called
the exogenic cycle of rocks.
This exogenic cycle is increasingly impacted by mankind. The radiation balance of
the atmosphere has been upset by the emission of carbon dioxide, methane and
other tracegases, Earth is warming. Industrially produced chlorinated hydrocarbons
have risen to the stratosphere, threatening the protective ozone layer. Dust from
traffic, industry and agriculture produce reagents which alter the air chemistry,
causing unprecedented interactions with the marine realm, with vegetation and even
with rocks through acidification, excessive deposition of nutrients and salts. Dry and
wet deposition of anthropogenic (i.e. produced by humans) particles can be
measured world-wide. The population explosion caused the intensification of
agriculture and the alarming loss of topsoil and cuts down on the extent of natural
ecosystems at the same time. The artificial fertilization of soils causes wide-spread
nitrate pollution of shallow ground waters and urbanization alters the water cycle
above and below ground. Local leakage and accidents with chemicals impact soil,
rivers and ground water. Civil engineering, discharges and denudation cause
alterations in almost all rivers world-wide and even coastal seas show increasing
eutrophication, siltation and ecosystem changes in the water column and in the
shallow sediments. The scars left by the mining of minerals and fossil energy are
visible everywhere and cause increasingly problems. Everywhere man has changed
the rate of natural processes. He spreads ever further into the landscape, utilizing
- 114 -

egions and building in areas which should not be used considering their natural
risks. Therefore damages through natural catastrophes rise traumatically
endangering the world insurance system.
All these processes and changes and their consequences are topics of
Environmental Geology. Understanding global change and accepting the
responsibility of mankind for this planet and its resources for future generations are
prerequisites for the planning of a sustainable development.
The division of Physical Geology and Geological Cycles at the Institute for Applied
Geo-sciences addresses several questions important to environmental geology both
in the present and in the geological past. These can be summarized as follows:
• Paleoclimatology (through the study of varved sediments in the Dead Sea Basin/
Jordan and in Lake Van/Turkey and through the study of speleothems)
• Carbonate geochemistry through time (through the study of alkaline crater lakes,
stromatolites and through modeling of early ocean conditions also for other
planets and moons of the solar system)
• Karst and cave development (through the studies of cave development in
limestone, gypsum and lava and through the study of cave deposits and their
paleontological content and geochemical composition)
• Biogeochemistry of rivers (through the study of the biogeochemistry of rivers such
as the Ebro and Rhine or in Patagonia).
Currently two German research funded projects are pursued, the reports of which
follow below.
Staff Members
Head
Research
Associates
Technical Personnel
Secretaries (Partial)
Diploma Students
Doctoral Students
Guest Scientists
Prof. Dr. Stephan Kempe
Dr. Jens Hartmann
Dr. Doris Döppes
Ingrid Hirsmüller
Jürgen Krumm
Kirsten Herrmann Monika Schweikhard
Clemens Schmidt
Hanna Wicke
Shahrazad Abu-Ghazleh Nils Jansen
Hans-Peter Hubrich
Prof. Dr. Ahmad Al-Malabeh, Hashemite University, Jordan
Prof. Dr. Kenji Okubo, Okayama University, Japan
Prof. Dr. Josef Kazmierczak, Polnische Akademie der
Wissenschaften
Dr. Hans H. Dürr, Utrecht University, Niederlande
- 115 -

Research Projects
Geomorphology and Paleoclimatology of Lake Lisan Terraces, Dead Sea, Jordan
(DFG, DAAD)
Publications
Hartmann, J.; Long-term seismotectonic influence on the hydrochemical composition
of a spring located at Koryaksky-Volcano, Kamchatka, deduced from aggregated
earthquake information, International Journal of Earth Sciences 95/4 (2006) 649.
Hartmann, J., Levy, J.; Seismotectonic influence on precursory changes in ground
water: Kobe earthquake, Japan, Hydrogeology Journal 14/7 (2006) 1307.
Hartmann, J., Levy, J., Okada, N.; Managing Surface Water Contamination in
Nagoya, Japan: An Integrated Water Basin Management Decision Framework, Water
Resources Management 20/3 (2006) 411.
Kazmierczak, J. & Kempe, S.; Modern analogues of Precambrian stromatolites from
caldera lakes of Niuafo'ou Island, Tonga, Naturwissenschaften 93 (2006) 119.
Kempe, S., Al-Malabeh, A., Al-Shreideh, A., Henschel, H.-V.; Al-Daher Cave
(Bergish), Jordan, the first extensive Jordanian Limestone Cave: A convective
Carlsbad-type cave?, J. Cave and Karst Studies 68/3 (2006) 107.
Jansen, N., Rüde, T.; Faziesabhängigkeit geogener Arsengehalte in Sedimenten der
Niederrheinischen Bucht, Schriftenreihe der Deutschen Gesellschaft für
Geowissenschaften SDGG, 43 (2006)
Kempe, S., Kempe, E. & Ketz-Kempe, C.; Die ersten Beschreibungen von Höhlen
durch Frauen: Lady Cravens Besuch der Höhle von Antiparos und Johanna
Schopenhauers Schilderung der Peaks Cavern, Natur und Mensch, Jahresmitteilung
2005 der Naturhistorischen Gesellschaft Nürnberg e.V. (2006) 19.
Kempe, S. Hubrich, H.-P. & Suckstorff, K.; The story of the 1833 Fercher Survey,
Postojnska jama, continues: An additional document and newly discovered
inscriptions, Acta Carsologica, 35/1 (2006) 131.
Kempe, S., Hubrich, H.-P., Suckstorff, K.; The history of Postojnska jama: The 1748
Joseph Anton Nagel inscriptions in jama near Predjama and Postojnska jama, Acta
Carsologica 35/2 (2006) 7.
Rosendahl, W.; Döppes, D.; Wollnashorn und Höhlenhyäne – eiszeitliches Treiben
im Odenwald, hessenArchäölogie 2005 (2006) 23.
- 116 -

Hydrogeology
Main research interests of the Hydrogeology Group are the fate of organic
contaminants in the subsurface and the development of novel methods to remediate
soil and groundwater contaminations. These areas are closely connected as the
application of effective clean-up technologies relies on a detailed understanding of
the chemical and physical processes in the subsurface.
Group Members
Head: Prof. Dr. Christoph Schüth
Research Associate: Dr. Matthias Piepenbrink
PD Dr. Peter Harres (- 31.05.06)
Technical Personnel: Rainer Brannolte
Secretaries: Angela Brezel
PhD Students: Dipl.-Geol. Meike Beier
Dipl.-Geol. Katy Unger Shayesteh
M.Sc. Flor Toledo Rodriguez
M.Sc. Shamsul Abedin Tarafder
M.Sc. Marina Nazarova
Dipl.-Geol. Guido Vero
Diploma Students: Timo Luchs Nils Michelsen
Research projects
Reversibility of sorption processes in natural and synthetic sorbents (2005-2007)
Diffusion, sorption and reactions in micro- and mesopores (2005-2007)
Implementation of a catalytic treatment system for groundwater contaminated with
chlorinated solvents (2005-2006)
Innovative technologies for groundwater remediation (2006 -)
Contaminated Datcha Areas in Sibira. Joint project with Material Sciences and WAR
(2006).
Management of regional water resources in arid areas – The Wajid aquifer in Saudi
Arabia (2006-2008).
Publications
Russold, S.; Schirmer, M.; Piepenbrink, M.; Schirmer, K. (2006): Modeling the Impact of a
Benzene Source Zone on the Transport Behavior of PAHs in Groundwater. Environ. Sci.
Technol. 40 (11), 3565-3571.
- 117 -

Engineering Geology
Engineering Geology is an applied earth science and a branch of the applied geology
which requires not only multidisciplinary knowledge within the natural sciences
(geology, chemistry, physics, mathematics), but still the engineering sciences. The
common aims of all special subjects contributing to engineering geology are the
investigation, the use, the protection and the remediation of the upper parts of the
earth's crust.
Regarding the worldwide rising importance of renewable energy resources,
Engineering Geology as the sciences which deals direct with the use of geothermal
energy is one of the future's most important applied geosciences. A highly qualified
geothermal lab and experimental hall is planned and will be realized starting in 2007
with first equipment.
Engineering Geology seizes the behaviour of rocks and rock masses according to the
genetic material properties and their earth-history development. It quantifies the
mechanical, physical and hydro mechanical characteristics and the behaviour of soils
and rocks in detail and in the assembly.
Important corresponding special subjects are the soil and rock mechanics, civil
services, foundation engineering, tunnel and cavity construction, drilling technology,
measurement engineering and applied subjects of hydrology and hydrogeology,
petrology and geochemistry. Engineering geology has thus strong relations with the
geotechnical engineering. It translates the results and knowledge of the geosciences
into the engineering requirements.
Thus, Engineering Geology contributes to the fact that buildings of all kinds can be
build and heated surely and economically. For this purpose the building ground and
other underground conditions for engineering structures, such as geothermal power
plants, traffic routes e.g. roads, bridges, tunnels as well as other infrastructure such
as caverns, dams, pipelines as well as buildings such as high rise buildings, halls,
wind power stations as well as water-structural plants such as water gates, dams,
dykes, are investigated.
Staff Members
Head
Research Associates
Ph.-D. Students
Technical Personnel
Prof. Dr. Ingo Sass
Dipl.-Ing. Ulrich Burbaum
Dr.-Ing. Thomas Nix
Dipl.-Ing. Marek Naser
Dipl.-Geol. Ulf Gwildis
Gabriela Schubert
Jürgen Krumm
Dipl.-Ing. Arne Buß
Rainer Seehaus
Secretary Kirsten Herrmann Monika Schweikhardt
- 118 -

Diploma Students
Guest Scientists
and Lecturers
Research Projects
Dipl.-Ing. Anne Minhans
Sebastian Homuth
Claudia Mack
Dipl.-Ing. Matthias Keil
Dr. Burkhard Sanner, European Geothermal Energy Council
Dr. Sven Rumohr, Hessian Agency for Environment and Geology
Interaction of Adhesive Soils, e.g. Clays and Steel Construction for Drilling
Tools e.g. Tunnel Boring Machines.
The adhesive behaviour of cohesive soils e.g. clays may cause an immense
decrease of the advance rate of tunnel boring machines or of a drilling process. The
chemical and physical properties of soils which causes adhesion are in research to
understand the processes of the jamming of boring tools. An adhesion measuring
device was developed:
Environmental and Geotechnical Behaviour of Polymeric Organic Additives for
Drilling Fluids for Tunnel Boring Machines
To reduce or to eliminate the jamming effects of adhesive soils, a polymeric organic
additive must be applicated to boring fluids. The additive has to be chosen according
to geotechnical criteria, which is affected by geological, hydrogeological and boring
aspects. After use, this boring fluid, mixed with soil, has to be deposited. This is
actually an environmental challenge due to the additive, so that the research in this
filed should bring up a clear understanding of the elution process.
Investigation on in situ Degradation of Urban Organic Lake Deposits using
Biodegradable Polymers
Organic lake deposits reduce the capacity of water storage reservoirs. To decrease
the capacity reducing volume of organic lake deposits, a polymer can be added to
the lake water. The biochemical effects are not well known yet. Therefore a research
project is in process using a lake in the city of Darmstadt. The research content a
broad field and laboratory test program on the lake deposits as well as the monitoring
of the volume of the lake deposits.
Investigation of River Dikes with Ground Penetrating Radar (GPR)
Flood waters cause financial, material and personal damages. Dikes are the most
important instruments of the flood protection. In Hesse, the first dikes were
constructed in the 15 th century. Since these times the dikes were extended, elevated,
repaired and renovated. Therefore, the dikes are not composed of a homogeneous
material but of various areas with different substantial and geotechnical properties.
To guarantee the stability of the dikes and to design the reconstruction measures,
complete information about the condition and the configuration of the dikes are
necessary. Common practices in dike investigations are soundings and small
drillings. These methods are only providing punctual information on the dike structure
and are invasive. A single gap in the information on the dike structure already means
to take a risk of a dike failure. Geophysical Investigations such as GPR, geoelectric
and seismic measures are providing two-dimensional continuous data. Among these
methods GPR affords the highest resolution and a fast investigation.
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Investigation of a Doline in NE-Hesse with GPR (Cooperation with HLUG).
The HLUG investigated a depression area in Bad Soden Allendorf. The geophysical
investigation concentrated on the expansion of a depression caused by carstification
of Permian (Zechstein) evaporite formation. The area is overbuilt with roads and
single housings. The depression is situated right beneath a street. Different
measures for stabilization and rehabilitation were under discussion. The investigation
with GPR helped to determine the expansion of the endangered area. With this
information, the covering was realized by a reinforced concrete plate.
Determination of the Thermal Properties of Soils using Geophysical Methods
especially Ground Penetrating Radar and Geoelectrical Methods
(RELGeotherm)
As the spatial distribution of thermal properties is important for the designing and
monitoring of geothermal installations, a non-invasive, high-resolution geophysical
investigation of the thermal properties is eligible.
The basis for a development of a geophysical investigation of geothermal properties
is the knowledge of the interrelation between geothermal and geophysical properties.
Preliminary investigation started to determine quantitatively the dependence of
geothermal properties on relative dielectric permittivity and electrical conductivity.
Improvement of Infiltration Potential Maps using Ground Penetrating Radar
(GPR)
To generate infiltration potential maps, infiltration tests are performed punctually.
Additionally, the geology and the land use are used to interpolate between these
tests. This information can be extracted from maps and other available geotechnical,
geological and other data and reports. The results of the infiltration tests are often
varying even though the geology and the land use are looking similar. These
variations are generated by small scaled discontinuities of the soils structure and the
composition in the shallow subsurface. To achieve a high resolution spatial
extrapolation of the results from infiltration tests, the structure and composition of the
shallow subsurface must be investigated with a high resolution. Especially the
hydrological properties are important. Therefore, the Infiltration process was
monitored in a natural soil on two test sites, in Darmstadt, TU-Lichtwiese and
Dieburg. The infiltration test was accomplished with a double ring Infiltrometer made
of plastic to minimize the influence on the measurements with GPR.
Determination of Hydraulic Properties of sintered HD-PE well Screens
Sintered High Density Polyethylene well screens are hydrophobic. The sintering
process allows control the pore sizes and tortuosity of pores. Additionally HD-PE
filters offer a large open entrance area for the filtrandum (groundwater). Preliminary
investigations have been accomplished to start an industry financed project in 2007.
In this project the hydraulic properties will be investigated in laboratory scale and in
the field.
Determination of Geothermal Properties of Soils and Rocks
For the dimensioning of Borehole Heat exchangers knowledge of thermal properties
of soil is needed. Presently only few data about these properties are existing.
Therefore, laboratory determination for the soils in the area of Calw (Germany) is
performed and a potential map will be developed.
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Publications
Burbaum, U. (2006): „Tragwerksplanung im konventionellen Tunnelbau“, Lecture in
Frankfurt, Symposium of Fa. Wayss & Freytag Ingenieurbau AG
Buss, A., Jahnke, C. (2006): Hydraulische Modellierung der hydrothermalen
Prozesse im Geothermiefeld Kizildere/Tekkehamam (Türkei) - In: Voigt, H.-J.,
Kaufmann-Knoke, R., Jahnke, C & Herd. R.: Indikatoren im Grundwasser -
Kurzfassung der Vorträge und Poster - Tagung der Fachsektion Hydrogeologie in der
DGG - 24.-28. Mai 2006, Cottbus. - Schriftenreihe der Deutschen Gesellschaft für
Geowissenschaften, 43: 116; Hannover.
Katzenbach, R. & Sass, I. (2006): Geothermal Summer School 2006.- lecture notes
of the advanced training programme, 380 p. TUD.
Katzenbach, R.; Sass, I.; Clauß, F. & Waberseck, T. (2006): Optimierung von
Erdwärmesonden in Bezug auf Boden- und Grundwasserverhältnisse sowie
Verpressmaterial - Qualitätssicherung - Tagungsband des 4. Forum Wärmepumpe,
Solarpraxis AG, Berlin, 26.-27. Oktober 2006
Katzenbach, R.; Sass I.; Clauß F.; Waberseck T. (2006): Geothermische Erkundung
zur Optimierung des Einsatzes erdgekoppelter Wärmepumpen, poster presentation
9. Geothermische Fachtagung, Karlsruhe, 15.-17. November 2006
Naser, M., Sass, I., Hornung, J., Hinderer, M. (2006): Geotechnische Untersuchung
von Deichen mit Georadar, Mitteilungen des Institutes und der Versuchsanstalt für
Geotechnik der Technischen Universität Darmstadt, Vorträge zum 13. Darmstädter
Geotechnik-Kolloquium, Hrsg.: Prof- Dr.-Ing. Rolf Katzenbach, Heft 73, 151-160
Sass, I.; Hoppe, A.; Burbaum, U.; Lerch, C., Wawrzyniak, C.: "Bauen im
Thermalwasserdistrikt - Geothermische Erkundung", poster presentation at the 9th
geothermal congress, 15. - 17.11.2006 in Karlsruhe
Sass, I. (2006): Bau und Ausbau von Erdwärmesonden, Qualitätssicherung, Vortrag
im Rahmen der Fortbildungsveranstaltung Geothermie der Fachsektion
Hydrogeologie in der Deutschen Gesellschaft für Geowissenschaften, am 11.Oktober
2006, Freiburg
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Applied Sedimentology
Sedimentary rocks cover about 75% of the earth’s surface and host the most
important oil and water resources in the world. Sedimentological research and
teaching at the Darmstadt University of Technology focus on applied aspects with
specific emphasis on hydrogeological, engineering and environmental issues.
However, also research related to oil exploration is carried out with a speciality in
palynology and reservoir characterization. To predict groundwater movement,
pollutant transport or foundations of buildings in sedimentary rocks a detailed
knowledge about the hydraulic, geochemical or geotechnical properties is needed
which often vary about several magnitudes. This kind of subsurface heterogeneity
can be related to distinct sedimentological patterns of various depositional systems.
In addition, changes of depositional systems with time can be explained by specific
controlling parameters e.g. changes in sea level, climate, sediment supply and are
nowadays described by the concept of sequence stratigraphy. The research in
applied sedimentology also includes modelling of erosion and sediment transport and
its implication for the management of rivers and reservoirs with the help of GIS.
In 2002, a georadar equipment has been established as a specific method for nearsurface
investigations. First results in the exploration of soils, rocks, and river dikes
could be achieved on various test sites in SW Germany. In the meantime, a centre of
near surface investigation methods has been founded by the Universities of Frankfurt
(Applied geophysics), Tuebingen (Applied sedimentology), Gießen (soil sciences),
industrial partners and the TU Darmstadt. Within this Center an instrumental pool is
shared, regular meetings are organised and research projects are initiated. In 2005,
self-constructed facilities for permeability measurements of soil and rock materials in
the laboratory went into operation. In 2006, two new DFG projects have been started
in the sedimentological research group. One is part of a DFG-Forschergruppe
together with the Universities of Frankfurt, Mainz and others. This joint research
group investigates the origin and evolution of extreme rift-flank uplift in East Africa
and its impact on climate, environment and the human evolution (see special
contribution). The other concerns the reconstruction of Miocene plate reorganisation
in western Mexico by interpretation of syntectonic volcaniclastic successions of the
Transmexican Volcanic belt.
Staff Members
Head Prof. Dr. Matthias Hinderer
Research Associates Dr.Jens Hornung Dr. Ulrich Bieg Dr. Sybille Roller
Technical Personnel Erich Wettengl
Secretaries Angela Bretzel
PhD Students Dipl.-Geol.
Inge Neeb
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MSc.
Crisanto Silva
Dipl.-Geol.
Nils Lenhardt

Diploma Students
Research Projects
Dipl.-Geol.
Frank Owenier
Dipl.-Geol.
Katrin Ruckwied
Kristian Bär Matthias Greb
Gunther Stapp
Dipl.-Geol.
Martin Kastowski
Sedimentary geology in general and reservoircharacterisation:
• Linking source and sink in the Ruwenzori Mountains and adjacent rift basins,
Uganda: landscape evolution and the sedimentary record of extreme uplift:
Subproject B3 of DFG Research Group RIFT-LINK “Rift Dynamics, Uplift and
Climate Change: Interdisciplinary Research Linking Asthenosphere,
Lithosphere, Biosphere and Atmosphere” (DFG HI 643/7-1)
• Volcaniclastic successions at the southern margin of the Transmexican
Volcanic Belt as witness of the Miocene plate reorganisation of the western
Mexican coast (DFG HI 643/5-1)
• The geology of raw materials, sequence stratigraphy and palynology in the
“Muschelkalk” of south Germany and Hungary. (Cooperation with University
Halle PhD thesis, DFG GO 761/1-1).
• Reservoir characterisation through outcrop analogue studies in a terminal
alluvial plain of the south German Keuper formation. (Studienarbeit)
• Comparison of Pangaean land locked successions (Upper Triassic;
Germany,Hungary, China): lithofacies make up, reservoir architecture and
depositional controls.
Quarternary sedimentary geology and surface processes:
• Sediment budget and sequence stratigraphy of Pliocene and Quaternary
unconsolidated deposits of the Rheingletscher area, Swiss midlands and the
Upper Rhein Graben (SPP International Continental Drilling Project; DFG HI
643/2-3; 2002-2005)
• Carbon burial in and CO2 evasion from Europe`s lakes and reservoirs (DFG
since August 2004 cooperation with University of Leipzig) – Hi 643/4-1.
• Genesis of alluvial fans and bajadas according to tectonical uplift and climate
change in the central Andes, Peru.
• Architecture, 3-dimensional sediment-mass partitioning and georisk
assessment of a debris flow fan in Switzerland (Diploma thesis).
Hydrogeology, engineering-geology:
• Characterisation of periglacial debris layers with ground penetrating radar in
terms of sedimentology, hydrogeology and soil-science (PhD thesis).
• Reconstruction of Holocene, Roman and modern sediment yield from valley
and reservoir fillings in the Huerva catchment, Ebro basin, Spain (PhD thesis
financed by DAAD).
• Geotechnical characterisation of radar facies patterns in river dykes as a
diagnostic tool for monitoring, quality management and
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econstruction.(Diploma thesis in cooperation with the Regierungspräsidium
Darmstadt).
• Water-rock interaction in the geothermal field Los Humeros, Central Mexico
(Cooperation with Centro de Investigaciones en Energia, Temixco, Mexiko)
(Diploma thesis and PhD thesis).
Publications
Hinderer, M. (2006): Stoffbilanzen in kleinen Einzugsgebieten Baden-Württembergs.
Grundwasser 11: 164-178. Springer-Verlag, Heidelberg.
Voigt, S., Haubold, H., Meng, S., Krause, D., Buchantschenko, J., Ruckwied, K. &
Götz, A.E. (2006): Die Fossil-Lagerstätte Madygen: Ein Beitrag zur Geologie und
Paläontologie der Madygen-Formation (Mittel- bis Ober-Trias, SW-Kirgisistan,
Zentralasien). - Hallesches Jahrb. Geowiss., Beiheft 22: 85-119, 4 Abb., 1 Tab., 6
Taf.; Halle (Saale).
Pleuger, J., Roller, S., Walter, J.M., Jansen, E. & Froitzheim, N. (2006): Structural
evolution of the contact between two Penninic nappes (Zermatt-Saas zone and
Combin zone, Western Alps) and implications for the exhumation mechanism and
palaeogeography. International Journal of Earth Sciences (Geologische Rundschau).
http://springerlink.com/content/e2610760582xj262/fulltext.pdf
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Geo-Resources and Geo-Hazards
Land use conflicts intensify in areas around growing cities where space becomes
increasingly valuable. To favour a sustainable land-use decision making, the
significance of geo-resources (e.g. groundwater, sand and gravel, soils) or geohazards
(sinkholes due to subrosion, heavy metals in rocks and soils) must be duly
considered, since geo-resources and geo-hazards are related to geological
structures and are therefore immovable. However, geological structures are usually
very complex in shape which makes them hard to understand for non-experts. A key
to their integration to decision processes is a comprehensible and transparent 3D
visualisation of the subsurface serving as a base for further two-dimensional thematic
maps which can be integrated in a GIS-based evaluation framework. Within this
framework, other information from economy, ecology or sociology can also be
integrated and evaluated together with geological data using a spatial decision
support system with multi-criteria techniques.
Staff Members
Head Prof. Dr. Andreas Hoppe
Research Associates Dr. Oswald Marinoni
Dipl.-Geoökol. Monika Hofmann
Dipl.-Geol. Stefan Lang
Technical Personnel Dipl.-Kartogr. (FH) Ulrike Simons
Holger Scheibner
Secretaries Kirsten Herrmann
Monika Schweikhard
PhD Students Lic. geogr. Teresa Lamelas Gracia
Students Andreas Deckelmann
Christian Tigler
Research Projects
A focus was set on evaluating and developing methods to support the sustainable
use of geo-resources in and around metropolitan areas. Our methods include the
enhanced implementation of outranking methods which still face computational limits
and have been refined by Oswald Marinoni (who left in autumn for CSIRO in
Brisbane, Australia), as well as existing methods which have been evaluated in
different case studies and presented during international meetings in Barcelona,
Bruges, Freiberg and Vienna (EGU and Karst Congress). The discussion within the
interdisciplinary “Forschungsschwerpunkt Stadtforschung” (Urban Sciences) at
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Darmstadt University of Technology (TUD) has been continued. Research
concentrated especially on the peripheries of three metropolitan areas:
(i) The Cenozoic terrestrial Hanau-Seligenstadt Basin between the Odenwald and
Spessart Mts with its important geo-potentials for the Rhine-Main Area has been
analysed with respect to its sedimentological and tectonic history and reported in a
dissertation by Stefan Lang. He also presented the results at international meetings
in Freudenstadt and Fukuoka/Japan. A first approach to evaluate the economic
potential of its raw materials supported by GIS-techniques has been performed in
cooperation with the TUD Institute of Economics (diploma thesis of Florian Schmidt,
orientated by Carsten Helm).
(ii) The evaluation of geo-resources and geo-hazards in the Ebro Basin in the
surroundings of Zaragoza, the fast growing capital of the Province of Aragón, Spain,
has been concluded by Teresa Lamelas Gracia. This project has been supported by
the DFG and performed in cooperation with Juan de la Riva from the Universidad de
Zaragoza. The dissertation report provides 68 thematic maps covering a broad
spectrum of regionalized information from geology, geomorphology, soils, water and
raw materials to natural protection areas,groundwater vulnerability and subrosionhazard.
The students Andreas Deckelmann and Christian Tigler have mapped an
area southeast of Zaragoza in great detail and proved the close correlation between
human irrigation activities and sudden sinkholes caused by dissolution of underlying
Miocene sulfates.
(iii) The investigations in the northern outskirts of Belo Horizonte (Minas Gerais,
Brazil), a fast growing metropolitan area supporting by now more than 4.5 million
inhabitants has been continued with field work by Monika Hofmann (supported by the
DAAD) in cooperation with Joachim Karfunkel from the Universidade Federal de
Minas Gerais. The study concentrated on erosion phenomena and landscape
changes due to extraction of raw materials. First results were presented at the
national meeting of Brazilian geologists in Aracajú.
A small project investigating the geothermal anomaly in the unsaturated zone within
the spa district of Wiesbaden (supported by the city of Wiesbaden) has been finished
by modelling the possible heat transfer in cooperation with the TUD Institute of
Energy and Powerplant Technology (Johannes Janicka) The investigations on the
eastern master fault of the Upper Rhein Graben under the future Science and
Congress Centre in Darmstadt (supported by Bauverein Darmstadt GmbH) have
continued.
Publications
Hoppe, A. (2006): Wasser im Nahen Osten – ein Kriegsgrund? Israel und die
Besetzten Gebiete im Kontext geologischer Entwicklung. – Naturwiss. Rundschau 59
(5): 241-247, Stuttgart.
Hoppe, A., Hofmann, M., Lamelas T.G., Lang, S., Lerch, C. & Marinoni, O. (2006):
Geo-Informationssysteme zur Bewertung von Geo-Potenzialen in der Peripherie von
Ballungsräumen.- Wiss. Mitt. Inst. Geol. TUB Freiberg (Kolloquium „GIS – Geowissenschaftliche
Anwendungen und Entwicklungen“), 31: 273-276, Freiberg.
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Hoppe, A., Lang, S., Lerch, C. & Marinoni, O. (2006): Geology and a spatial decision
support system for the surroundings of urban areas: An example from southern
Hesse (Germany). - Z. dt. Ges. Geowiss. 157: 135-146, Stuttgart.
Hoppe, A., Lerch, C. & Lang, S. (2006): Detailed estimates of groundwater
vulnerability using three dimensional geological models.- Proc. 5. Europ. Congr. Reg.
Geoscient. Cartogr. Inform. Syst. vol. 1: 35-37, Barcelona (13.-16.6.2006).
Lamelas, T., Marinoni, O., Hoppe, A. & de la Riva, J. (2006): The use of spatial
decision support systems for sand and gravel extraction suitability in the context of a
sustainable development in the surroundings of Zaragoza (Spain).- Proc. 5. Europ.
Congr. Reg. Geoscient. Cartogr. Inform. Syst. vol. 2: 180-183, Barcelona (13.-
16.6.2006).
Lamelas, T., Marinoni, O., Hoppe, A. & de la Riva, J. (2006): Sustainable land-use
management with the help of spatial decision support systems: An example of a
covered karst area in the surroundings of Zaragoza (Spain).- Proc. Int. Conf. “All
about Karst & Water – Decision Making in a Sensitive Environment”, 58-67, Vienna.
Lang, A., Bartholomä, A., Hoppe, A. & Lerch, C. (2006): Einblicke in den Untergrund
– Flachwasser-Seismik auf dem Main. – Natur und Museum 136: 15-19, Frankfurt
a.M.
Marinoni, O. (2006): A discussion of the computational limitations of outranking
methods for land-use suitability assessment. – Int. J. Geogr. Inform. Sci. 20 (1): 69-
87.
Marinoni, O. & Hoppe, A. (2006): Using the Anaylitical Hierarchy Process to support
the sustainable use of geo-resources in metropolitan areas. – J. Syst. Sci. Syst.
Engin. 15 (2): 154-164, Tsinhua.
Nix, T. & Marinoni, O. (2006): Quantitative landslide risk analysis and risk evaluation
for publicly accessible geosites.- Int. Assoc. Engin. Geol. Conf., 12 pp., Nottingham
(6.-10.9.2006).
Striegler, K., Fettel, M. & Hoppe, A. (2006): Bergbauspuren im Odenwald. – Z.
Gesch. Berg- u. Hüttenwesen 12 (2): 4-95, Idar-Oberstein.
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Geomaterials Science
Geomaterial Science (Applied Mineralogy) explores formation/processing conditions,
composition, microstructure and properties of minerals, rocks and synthesized compounds,
where the latter reveal a wide variety of industrial applications. The research focuses on a
comprehensive characterization of the relevant natural and synthetic phases, their
performance under pressure, temperature, deformation and local chemical environment as
well as tailored synthesis experiments for high-tech materials.
The experimental studies focus on the crystal chemistry of minerals and synthetic
compounds, in particular, their crystal structure, phase assemblage, deformation behaviour
and microstructure evolution. The microstructure variation (e.g., during exposure to high
temperature) has an essential effect on thermo-mechanical and electrical properties of
synthetic materials as well as natural minerals, which in turn can be used to reconstruct the
mechanical and thermal history of rock during sub- or obduction processes.
An important facet of the Fachgebiet Geomaterial Science (and Environmental Mineralogy of
Prof. Weinbruch) at the Institute of Applied Geosciences is the application of electron
microscopy techniques for the detailed micro/nano-structural characterization of solids. Here,
transmission electron microscopy (TEM) in combination with spectroscopic analytical
methods such as energy-dispersive X-Ray spectroscopy (EDS), electron energy-loss
spectroscopy (EELS) and energy filtered imaging (GIF) are the main tools employed for
detailed microstructure and defect characterization. High-resolution imaging of local defects
on the atomic scale in addition to chemical analysis with high lateral resolution (down to a
few nanometers) is similarly applied to high-performance ceramics, natural minerals,
meteorites and corrosion phenomena.
Recent research projects involve topics such as fatigue of ferroelectrics, re-calibration of the
clinopyroxene-garnet geothermometer with respect to small variations in the Fe 2+ /Fe 3+ -ratio,
formation temperature of meteorites, defect structure in Bixbyite single crystals and
transparent ceramics based on the spinel structure.
Future research activities will include investigations on interface structures in polycrystals,
high-temperature microstructures and the study of biomaterials based on hydroxylapatite.
Staff Members
Head Prof. Dr. Hans-Joachim Kleebe
Research Associate Dr. Stefan lauterbach
Technical Personnel Bernd Dreieicher
Secretary Betina Schubotz
PhD Students N.N.; Fe-Mg Geothermometer
Jens Kling; SFB-595 (co-supervision with Prof. H. Fueß)
Guest Scientists Prof. Dr. Wolfgang Müller
Dr. Avanish Srivastava, New Delhi, India
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Research Projects
Transmission electron microscopy of ultrahigh pressure metamorphic eclogite from
the Chinese Continental Scientific Drilling project at Donghai (DFG 2006-2008, Prof.
Wolfgang Müller in collaboration with Z. Xu, Institute of Geology, Chinese Academy
of Geological Sciences).
Rapid Exhumation of the Eclogite Zone in the Tauern Window: Deformation Effects in
Eclogite Minerals Close to the Interface Eclogite Zone/Lower Schist Cover (scientific
interaction 2005-2009), Prof. Wolfgang Müller in collaboration with G. Franz, TU
Berlin).
Thermal History of Chromite Layers and Iron-Rich Rims in Chondrules of the Allende
Meteorite (scientific cooperation 2006-2007 with Prof. Stefan Weinbruch and PD Dr.
Peter van Aken).
Planar Defects in Bixbyite, (Mn,Fe)2O3; A Prominent Diffusion Path (scientific
cooperation 2005-2008 with Dr. Alexander Rečnic, Jožef Stefan Institute, Ljubljana,
Slovenia).
The Effect of LiF Addition on the Sintering Mechanism of Spinel, MgAl2O4 (scientific
collaboration 2005-2008 with Prof. Ivar E. Reimanis, Colorado School of Mines,
Golden, CO, USA).
Microstructure Characterization of Boron Suboxide, B6O (scientific interaction 2006-
2008 with Prof. Jack Sigalas, School of Chemical and Metallurgical Engineering,
University of the Witwatersrand, Johannesburg, Gauteng, South Africa).
Temperature and Pressure Dependence of the Fe 2+ /Fe 3+ -Ratio in Omphacite for Re-
Calibration of the Fe-Mg Geothermometer (DFG 2006-2008).
Deformation Experiments on Omphacite at Pressure and Temperature Conditions of
High Pressure Metamorphism (Prof. Wolfgang Müller, 2005-2008, in collaboration
with N. Walte, N. Miyajima, D. Frost, Bavarian Geoinstitute, Bayreuth).
Microstructures of Eclogite Minerals from the Ultrahigh Pressure Metamorphic Unit at
Lago di Cignana, Western Alps, Italy (Prof. Wolfgang Müller, 2005-2008, in
collaboration with R. Compagnoni, Torino, Italy).
Publications
Ayers, R.; Nielsen-Preiss, S.; Ferguson, V.; Gotolli, G.; Moore, J.J.; Kleebe, H.-J.;
Osteoblast-like cell mineralization induced by multiphasic calcium phosphate
ceramic, Mater. Sci. Eng., C 26 (2006) 1333.
Gregori, G.; Kleebe, H.-J.; Mayr, H.; Ziegler, G.; EELS characterization of β-tricalcium
phosphate and hyrdroxyapatite, J. Eur. Ceram. Soc., [8] (2006) 26, 1473.
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Gregori, G.; Kleebe H.-J.; Sorarù, G.D.; Energy-filtered tem study of Ostwald ripening
of Si nanocrystals in SiCO glasses, J. Am. Ceram. Soc., 89 [5] (2006) 1699.
Gregori, G.; Kleebe, H.-J.; Blum, Y.D.; Babonneau, F.; Evolution of C-rich SiOC
ceramics, part-II. Characterization by high lateral resolution techniques: electron
energy-loss spectroscopy, high-resolution TEM and energy-filtered TEM, Int. J. Mat.
Res., 97 [6] (2006), 710.
Guo, L.; Singh, R.N.; Kleebe, H.-J.; Growth of boron-rich nanowires by chemical
vapor deposition (CVD), J. Nanomat., 1 [58237] (2006) 1.
Kleebe, H.-J.; Gregori, G.; Babonneau, F.; Blum, Y.D.; MacQueen, D.B.; Masse, S.;
Evolution of C-rich SiOC ceramics, part-I. Characterization by integral spectroscopic
techniques: solid-state NMR and Raman spectroscopy, Int. J. Mat. Res., 97 [6]
(2006), 699.
Lehner, W.; Kleebe, H.-J.; Ziegler, G.; Variation of sintering parameters at an early
stage of densification affecting β-Si3N4 microstructure, J. Eur. Ceram. Soc., 26 [2]
(2006) 201.
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Technical Petrology
with emphasis in Low Temperature Petrology
The scientific and educational field of this 35 years young branch within the applied
geosciences is based on indispensable knowledge in magmatic, metamorphic
(greenschist facies to ultra-metamorphism) low-temperature (studies in diagenesis
and sub-greenschist facies metamorphism) and hydrothermal petrology but also in
geothermal geology and sediment petrography. On these fundamentals it is possible
to evaluate the mechanical, chemical and physical properties of rocks and the
determination for their technical use in engineering geology, in environmental
sciences, in geo-material and thermal-energy sciences. The determination of the
genetic history and evolution of rocks through time and space gives, e.g., basic
information on the study of rock and ore deposits for prospection and exploitation
interests. To understand mineralization, re-crystallisation and petrogenesis of rocks
an important effort is focussed on tectono-thermal research, tectonophysics and
structural geology (from the kilometre to nanometre scale). Furthermore, many
natural processes are catalytically controlled by deformation. A better understanding
of these processes can be recorded from deformation versus crystallisation and
deformation versus metamorphism/ heating studies in the field and by experimental
simulations. Therefore technical petrology is strongly field-oriented and linked to
mineralogy, structural geology and also to geochemistry. Technical petrology in our
department will be centred on low-temperature petrology with strong relations to
applied mineralogy (geomaterial science), applied sedimentology and geothermal
science, three other fields of principal interest at the TU Darmstadt.
Low Temperature Petrology covers a broad field of studies: - on diagenesis with
application in hydrocarbon, hydrothermal and geothermal exploration, - on clay and
carbonaceous materials related with applied organic and clay petrology studies, - on
maceral analysis of coals, - on sorption properties of carbonaceous and clay
materials, - on the determination of graphitisation nano- and microstructures
(refractory quality), - on the improvement of forward numerical geothermal, and
maturity, and basin-analysis models (studies on hydrocarbon and fluid migration) - or
on the synthesis of graphite structures and organic matter maturity related to
technical aspects, - on recognizing of soot and carbon black in filtering installations or
the thermal resistance of organic particles among other applications. It is important to
understand the chemical and physical parameters of natural systems to be able to
recognize the differences caused by anthropogenic changes.
In the low-temperature range, neoformation of mesoscopic and macroscopic phases
is very rare and the minerals to be studied have a very small grain-size. Also stable
thermodynamic conditions are scarce and metastable phases and chemical
disequilibria conditions are very common. Therefore a broad analytical spectrum
must be applied. In the FG Technical Petrology, general microscopy (MPV coal
reflection microscopy, fluorescence microscopy, transmitted light microscopy in the
Joint Research Microscopy Laboratory, installed in 2004 and supported by the
Mineralogisch Petrographisches Institut Basel, CH) and basically XRD powder and
texture studies (Clay and XRD Laboratory, installed in 2005) can be combined with
ICP-AES, TOC, AAS, AOX and gas chromatography (GC-ECD, GC-MS) in the
Organic Geo-chemical Laboratory (recently installed with thankful help by the
- 131 -

Hessische Industriemüll GmbH). Due to the small size, also fluid inclusion studies,
DTA, TGA, AEM, TEM, HRTEM, Raman spectroscopy, EELS and XAS give
important hints to low temperature petrologic researches (in collaboration with
research groups of the GEO-initiative Rhein-Main – Darmstadt, Mainz, Frankfurt).
The main research interests of the study group of R. Ferreiro Mählmann (head of the
group since August 2002) are concentrated in the petrological and petrographical
study of tectono-metamorphic orogenic terrains (Alps, Vosges, Carpathians, Andes,
New Caledonia). The major aim is to discriminate specifically between pre-, syn- and
post-kinematic metamorphic events to get a better understanding of the orogenic
processes that were active during subduction, collision, stacking and exhumation in
several parts of mountain belts. More specifically research is concentrated on
diagenesis and low-temperature metamorphism, dealing primarily with pelites and
rocks rich in organic matter. Here the principal interest is focussed on the study of
vitrinite, bituminite and secondary macerals, important constituents of coals and the
main source for oil and gas formation and economic reservoirs. In low-grade
metamorphic studies reaction-disequilibrium is a frequent factor and is documented
through the irregularity of the alteration processes of mineral and organic matter
reactions. The research is concentrated on the application of field-petrology and
mineralogical laboratory methods to problems related to equilibrium and
disequilibrium conditions.
R. Le Bayon (assistant since December 2004) focuses his research on the
metamorphic petrology concerning silicate bearing-rocks and on organic matter
maturity and graphitization. One of the aims of metamorphic petrology is to determine
the pressure-temperature history of natural rocks, and thus to aid understanding of
orogenic processes. Magnesian metamorphic rocks with metapelitic mineral
assemblage and composition are of great interest in metamorphic petrology for there
ability to constrain P-T conditions in structural units where metamorphism is not
mesoscopically and macroscopically visible. The principal goal of the study
(associated with C. de Capitani – University of Basel, CH) is to improve
understanding of the phase relationships in magnesian metapelites with bulk
compositions mostly comprised by the system K2O – FeO – MgO – Al2O3 – SiO2 –
H2O (KFMASH) as a function of pressure, temperature, water activity and bulk-rock
composition, and thus to constrain and interpret large-scale geodynamic evolutions.
Another aim of R. Le Bayon (associated with C.J. Hetherington – University of
Boston, USA) concerning the Si-bearing metamorphic rock was to determine the
pressure-temperature evolution recorded by chemically zoned crystal. Chemical
zoning of prograde metamorphic minerals is commonly attributed to net transfer
reactions, intra-crystalline diffusion or the growth of compositionally differing zones of
the same phase during consecutive geological events. The study is devoted to
understand complex chemical zonation recorded in garnet grains. For a given bulk
rock chemistry, equilibrium phase diagrams are calculated over a specified P-T range
using thermodynamic software. Metamorphic minerals of a facies critical paragenesis
are identified and their isopleths calculated to model the variation in composition of
each phase in response to variations in pressure and temperature. The modelled
chemical changes are compared with the observed chemical zoning and the Alpine
metamorphic history of the gneiss and its garnet grains is reconstructed. The
modelling of the prograde mineral reactions using a bulk rock composition, combined
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with observed chemical zoning in metamorphic minerals, is a valuable method for
constraining the prograde P-T path when standard methods are inapplicable.
To understand metamorphic mechanisms and to model kinetic evolution of the
maturation of organic matter, R. Le Bayon (associated with G. Brey – University of
Frankfurt am Main, D; L. Nasdala – University of Vienna, A; W.G. Ernst – University
of Stanford, USA) is carrying pressure-temperature-time experiments at the
mineralogical institute of the University of Frankfurt am Main. This modelling will
serve as a tool to better understand and constrain the pressure-temperature-time
evolution of carbonaceous-bearing metamorphic rocks.
The studies of H. Hofmann (assistant since August 2004) are based in the research
field of applied clay mineralogy, e.g. geochemical processes related to the formation
of bentonites by the low- grade alteration of volcanic ashes and tuffs. Bentonites,
namely the swelling smectites, are most important to a large number of industrial and
technical applications due to their special physico-chemical properties like sorption
capacity for water, cations and organic complexes, as well as high swelling- and
sealing capacity. Possible technical and geotechnical applications related to these
properties are located in the pharmaceutical – and oil industry, and since a couple of
years in the secure disposal of radioactive waste. Each of these applications requires
different material properties. Despite the fact that most of the properties of smectites
are quite well known physically and chemically, it is not yet clear where they originate
from and how fast material properties can change if the environmental conditions
change. To be able to predict if and how the material will change under extreme
conditions like they are present in a nuclear waste disposal site, it is essential to
know how fast the material can adapt to new environmental conditions.
Bentonites are formed by alteration of volcanic ashes and tuffs, partly millions of
years ago. However, it is not well known, when under which conditions the alteration
process initiated, and how much time is required to form the swelling clays. It is
attempted to determine the kinetics of the reaction progress and the controlling
factors of physico-chemical property changes responding to different environmental
conditions.
The main projects of D. Scheuvens, collaborating with M. Hinderer (FG Applied
Sedimentology) and E. Stein in the Odenwald mountains is based on a rock-registry
survey jointly with the IFS (Institut für Gesteinskonservierung) and the UNESCO
Geopark Bergstraße-Odenwald centre. E. Stein also investigates the interplay of
plutonism, deformation and metamorphism in the eastern part of the `zone axiale´ of
the Montagne Noire (southern France), a classical geological region to study the
burial and exhumation of rocks.
Staff Members
Head Prof. Dr. Rafael Ferreiro Mählmann
Research associates Dr. Ronan Le Bayon, PD Dr. Eckardt Stein
Dr. Heiko Hofmann, Dr. Dirk Scheuvens
- 133 -

Technical Personnel Josef Kolb, Dipl.-Ing. Zahra Neumann
Secretary Natali Vakalopoulos
Research Projects
Experimental kinetic study of organic matter maturation: an appraisal of
pressure, temperature and time effects on reflectance properties of vitrinite. -
(DFG, Cooperation with University of Frankfurt a. M., D; University of Vienna, A
and Stanford University, USA).
Geochronology and tectono-thermal history of the Penninic-Austroalpine boundary
(Arosa Zone) in Eastern Switzerland; a multi-methodical comparison of methods. -
(SNF, Willkomm Fond, cooperation with University of Bern, CH and Departement für
Zivilschutz, Bern, CH).
Deformation, fluid flow and mineral reactions along the Glarus overthrust and along
the extensional Turba Mylonite Zone, eastern Swiss Alps, Switzerland. Effects of
tectonic shear strain on phyllosilicates and organic matter. - (SNF, OTKA Hungary,
August Collin Fond cooperation with University of Basel, CH; University of Genève,
CH; University of Budapest, HU; Johns Hopkins University Baltimore, USA).
Bituminite parameters to determine thermal metamorphism - field data and
experimental studies. - (cooperation with University of Chile, Santiago de Chile, CL;
Institutul Geologic al Romaniei, Bucharest, RO; University Complutense, Madrid, E;
Stanford University, USA; University of Gießen, D; Peking University, China and ETH
Zürich, CH).
Effect of contact metamorphism on very low-grade parameters: a natural laboratory
study in the Vosges (France) - (Cooperation with University of Frankfurt a. M., D).
Publications
Potel, S.; Ferreiro Mählmann, R.; Stern, W.B.; Mullis, J.; Frey, M.; Very low-grade
metamorphic evolution of pelitic rocks under high-pressure/low-temperature
conditions, NW New Caledonia (SW Pacific), Journal of Petrology, 47/5 (2006) 991-
1015.
Le Bayon, R.; De Capitani, C.; Frey, M.; Modelling phase-assemblage diagrams for
magnesian metapelites in the system K2O – FeO – MgO – Al2O3 – SiO2 – H2O:
geodynamic consequences for the Monte Rosa nappe, Western Alps, Contributions
to Mineralogy and Petrology, 151 (2006) 395-412.
- 134 -

Environmental Mineralogy
Environmental mineralogy focuses its research on the characterization of individual
aerosol particles by electron beam techniques (high-resolution scanning electron
micro-scopy, transmission electron microscopy, environmental scanning electron
microscopy).
We study individual aerosol particles in order to derive the physical and chemical
properties (e.g. complex refractive index, deliquescence behavior) of the atmospheric
aerosol. These data are of great importance for modeling the global radiation balance
and its change due to human activities.
We are also interested in studying the particulate matter exposure at working places
and in urban environments. As aerosol particles may have adverse effects on human
health, the knowledge of the particle size distribution and the chemical and
mineralogical composition of the particles is of prime importance in order to derive
the exact mechanisms of the health effects.
Our research is carried out in cooperation with the following national and international
partners: Max Planck Institute for Chemistry (Department of Biogeochemistry) in
Mainz, Institute for Atmospheric Physics (University of Mainz), Forschungszentrum
Karlsruhe (Institut für Meteorologie und Klimaforschung), Institute for Tropospheric
Research in Leipzig, Paul Scherrer Institut (Laboratory of Atmospheric Chemistry) in
Villigen (Switzerland), National Institute of Occupational Health in Oslo (Norway), and
McDonnell Center for the Space Sciences in St. Louis (USA).
Other fields of research include kinetics of mineral reactions and cosmochemistry.
Staff Members
Head
Prof. Dr. Stephan Weinbruch
Research Associates Dr. Nathalie Benker
Dr. Martin Ebert
Dr. Konrad Kandler
Dipl.-Met. Dörthe Müller-Ebert
Dr. Annette Worringen
Dr. Frank Zimmermann
Technical Personnel
Secretary
PhD Students
Thomas Dirsch
Astrid Zilz
Dipl.-Min. Marion Inerle-Hof
Guest Scientist Dr. Marie Choël (University of
Wimereux, France
- 135 -

Research Projects
Environmental scanning electron microscopical studies of ice-forming nuclei (SFB
641; “Die troposphärische Eisphase” (2004-2007).
Electron microscopy of Saharan mineral dust (DFG Forschergruppe SAMUM) (2004-
2010).
Source apportionment of rural and urban aerosols.
Characterization of working place aerosols (National Institute of Occupational Health,
Oslo, Norway)
Environmental scanning electron microscopical studies of the hygroscopic behaviour
of individual aerosol particles.
Publications 2006
Ebert, Martin; Der Staub in unserer Atmosphäre, in: Staub, Spiegel der Umwelt, J.
Söntgen und K. Völzke, Ed. Oekom Verlag (2006) 83-96.
Mazurek, M.; Benker, N.; Roth, C.; Buhrmester, Th.; Fuess, H.; Electrochemical
Impedance and X-ray absorption spectroscopy (EXAFS) as in-situ methods to study
the PEMFC anode, Fuel Cells 6 (1) (2006) 16-20.
Benker, N.; Roth, C.; Mazurek, M.; Fuess, H.; Synthesis and characterisation of
ternary Pt/Ru/Mo catalysts for the anode of the PEM fuel cell, J. New Mat.
Electrochem. Sys. 9, (2006) 121-126.
Mazurek, M.; Benker, N.; Roth, C.; Fuess, H.; Structural and electrochemical
investigation of binary mixtures of carbon-supported Pt and Ru catalysts for PEM fuel
cells, Fuel Cells 6 (2006) 208-213.
Thomassen Y.; Koch W.; Dunkhorst W.; Ellingsen D.G.; Skaugset N.P.; Jordbekken
L.; Drabløs P.A.; and Weinbruch S.; Ultrafine particles at workplaces of a primary
aluminium smelter, J. of Environmental Monitoring, 8, (2006)127-133.
Weinbruch S.; Styrsa V.; and Dirsch T.; The size distribution of exsolution lamellae in
iron-free clinopyroxene, American Mineralogist, 91, (2006) 551-559.
Zimmermann F.; Matschullat J.; Brüggemann E.; Plessow K.; Wienhaus O.;
Temporal and elevation-related variability in precipitation chemistry from 1993 to
2002, eastern Erzgebirge, Germany, Water, Air, and Soil Pollution 170 (2006), 123-
141.
Zimmermann F.; Plessow K.; Queck R.; Bernhofer C.; Matschullat, J.; Atmospheric
N- and S-fluxes to a spruce forest – Comparison of inferential modelling and the
throughfall method, Atmospheric Environment 40 (2006), 4782-4796.
- 136 -

Reports of Research Activities
The terraces of Lake Lisan: a continuous record of the
climatic changes during the Late Pleistocene.
Shahrazad Abu Ghazleh and Stephan Kempe
Lake Lisan filled the Dead Sea depression between 63-15 Ka B.P. (Kaufmann et al.,
1992; Shramm et al., 2000). The regression of the Lake Lisan to the current Dead
Sea led to a sequence of shore terraces (Fig. 1) that offer excellent possibilities to
reconstruct the lake history and correlate it with climatic changes during the Late
Pleistocene.
Five cross sections of these terraces were examined by differential GPS altimetry.
The terraces were found to be horizontal, undisturbed and characterized by a gentle
foreshore with a slope of 3.5-12 degrees and a steep backshore with slope of 12-27
degrees. The terraces range in elevation between -370 and -117 m (i.e. below sea
level) that represent the levels of the lake in Late Pleistocene and suggest (a) a much
higher stand of Lake Lisan at -117 m (Fig. 2) than the previous known level of -150 m
(Bowmann and Gross, 1992); (b) a sharp but gradual drop of the lake from a very
high level at about -117 m to a very low level at about -370 m; (c) substantial climatic
changes in the Jordan valley during the Late Pleistocene from initially very wet
conditions to extremely dry conditions.
On these terraces - between -370 and -148 m - in-situ precipitated, calcareous
stromatolites are preserved. Some form large, laminated, massive, head-like blocks
others are finely laminated crusts. Since stromatolites are formed on algal mats, they
are indicative of relatively shallow water conditions. Calcareous crusts less clearly
laminated and more clotty in structure appear between -148 and -117 m. This may
indicate (a) that the lake chemistry at high lake stands was less alkaline due to high
fresh water input; or (b) that the wave action was stronger at the steep eastern shore
of Lake Lisan, formed by Cambrian sandstones and dolomites. Dating stromatolites
with 14C and U/Th and of the terraces sediments by OSL is in progress.
- 137 -

Fig. 1: Aerial photo of the Lake Lisan terraces in Numirah area/ Eastern Coast of the Dead Sea.
Fig. 2: The high terraces of Lake Lisan at -117 m in the Eastern Coast of the Dead Sea.
- 138 -

High riverine fluxes of dissolved silica from Japan – the
influence of lithology
J. Hartmann 1 , N. Jansen 1 , H.H. Dürr 2 , S. Kempe 1
1 Institute for Applied Geosciences, Darmstadt University of Technology, Germany,
2 Department of Physical Geography, Utrecht University, Netherlands
Silicate weathering is a significant sink for atmospheric CO2 and thus relevant for
climatic processes. Weathering rates are controlled by climate, vegetation, land use,
relief and particularly lithology. It was hypothesized that volcanic islands and back arc
basins are hyperactive with respect to silicate weathering. This is due to the high
content of easily weatherable Ca + Mg-silicate minerals abundant in volcanic rocks.
This work analyzes the influence of lithology on specific silica fluxes. Data from 262
river chemistry monitoring locations were used as well as a newly developed
lithological map (Fig. 1). It distinguishes 15 lithologic units. According to this
classification the lithology of Japan is assembled of 13% plutonic rocks, 32% volcanic
rocks, 49% sediments and 5% metamorphites, contrasting with the world average
lithology that consists of 7% plutonic rocks, 7% volcanic rocks, 64% sediments and
16% metamorphites. 65% of the surface area of Japan are documented by the data
set and the average silica flux for this area is 22 t · km -2 · a -1 . This value is 6.7 times
higher than the world average of 3.3 t · km -2 · a -1 (Dürr et al., in prep.). Despite its
small size, Japan discharges 2.1% of worldwide riverine dissolved silica fluxes into
coastal waters. The specific silica flux of the most productive watershed is as much
as 84 t · km -2 · a -1 . The watersheds containing more than 80% volcanic rocks are
characterized by an average specific silica flux of 40 t · km -2 · a -1 . This stretches out
the importance of volcanic rocks for weathering rates and CO2 uptake respectively.
Reference:
Dürr, H., Meybeck, M., Sferratore, A. & Hartmann, J. (in preperation): Estimating
silica fluxes to the coastal zone using a global segmentation, for C.R. Geosciences
- 139 -

Lithological Map of the
Japanese Archipelago
Fig 1: Newly developed lithological map of Japan.
- 140 -

Groundwater treatment technologies
Christoph Schüth
Contamination of groundwater with organic contaminants, especially chlorinated
hydrocarbon compounds (CHCs) and petroleum hydrocarbons as constituents of
gasoline, is a wide-spread problem in industrialized countries. The treatment of the
contaminated groundwater is in
most cases achieved by
pumping it through an
adsorbent on-site, e.g. granular
activated carbon (GAC). The
efficiency of such a system can
be further increased by air
stripping the contaminants, as
the sorption capacities of these
compounds on GAC are
increased out of the gas-phase,
due to the minimization or
absence of competitive effects
of the groundwater itself or
other groundwater solutes.
Fig. 1: HFM module. The contaminated groundwater
enters the module at one side and flows over the
shellside (outside) of the hollow fibers to the outlet.
Nitrogen is used as an inert strip gas and is applied
on the lumenside (inside) of the hollow fibers in
counterflow.
Furthermore, alternative
destructive treatment options for the gas phase exist, e.g. catalytic oxidation, or
reductive catalysis especially for chlorinated compounds.
Packed tower aeration is the
most common stripping
method, although it has
several disadvantages. An
alternative approach is the
use of polypropylene hollow
1
100
fiber membrane modules
(HFM), that are routinely
used for the degassing of
process waters e.g. in the
electronics industry or for
0.1
50
the deaeration of bottled
beverages (Fig. 1). With a
very small footprint, these
units provide a large surface
area for mass transfer and
enable an independent
control of gas and liquid flow
rates without the risk of
flooding. Volume specific
overall mass transfer
coefficients for HFM
0.01
0
0.01 0.1 1
H (-)
Fig. 2: Removal efficiencies for the 12 compounds using
three
different experimental conditions (water flow rate
constant
tant at 0.4 l/min, gas flow and pressure combinations
of 2.0 l/min and 0.25 atm (open circles), 0.8 l/min and 0.1
atm (solid circles), 0.4 l/min and 0.05 atm (solid triangles)
respectively, resembling constant Ra/w ratios of 20, and
co rresponding mass balances (symbols with dotted lines).
stripping have been reported to be an order of magnitude higher compared to packed
C/C0 (-)
NAP
1,1,2,2-TCA
MTBE
- 141 -
1,2-DCA
1,2-DCB
1,4-DCB
CB
cis-1,2-DCE
TOL
TCE
PCE
1,1-DCE
Mass balance (%)

tower stripping, and therefore much lower strip-gas to water flow ratios are needed for
an effective stripping.
The removal of 12 organic contaminants from water using a HFM module was studied
under low strip gas flow to water flow ratios (up to 5:1). Removal efficiencies were found
to be strongly dependent on the Henry’s law constants indicating a substantial mass
transfer resistance on the gas side. Vacuum can be either used to increase removal
efficiencies, or to decrease the amount of strip gas that has to be treated without
sacrificing efficiency (Fig. 2).
The conventional resistance in series model was inapplicable to predict mass transfer
coefficients in our experiments as it assumes, that at least for the operation conditions
used here, the liquid side mass transfer resistance dominates the overall resistance for
all compounds (Fig. 3, left). Therefore, a new hybrid numerical and analytical modeling
approach in the finite element simulator RockFlow/GeoSys for hydraulic flow and mass
transport was developed. This approach enables the prediction of the removal
efficiencies within a few minutes, whereas a pure numerical approach would require
several hours to days due to numerical stability controls. The input parameters for the
model are defined by the geometry of the HFM and the operating conditions, no
empirical formulations are applied.
The model allows the investigation of the main factors controlling the removal
characteristics, e.g. the dependency on Henry’s law coefficient, gas side diffusional
Kcalc (m/s)
3.0e-5
2.0e-5
1.0e-5
0.0
0.0 1.0e-5 2.0e-5 3.0e-5
K exp (m/s)
C/C0 (-) m odel
0.001
0.01
0.1
1
1
0.1
0.01
C/C0 (-) experimental
Fig. 3: Left: Calculated overall mass transfer coefficients K vs. experimental K.
Calculations based on the resistance in series model. Right: Comparison of the
experimental removal efficiencies (C/C0, with C being the outflow aqueous concentration
and C0 being the inflow aqueous concentration) with the removal efficiencies calculated
by the proposed model.
resistance, and aqueous diffusion limitation, and also enables the efficient design of
further organic removal systems based on the HFM technology. The model was able to
predict removal efficiencies for all experimental conditions with reasonable accuracy
(Fig. 3 right).
- 142 -
0.001

As the second step of the treatment method, the catalytic conversion of several organic
contaminants was studied at elevated temperatures (50°C – 400°C) in the gas phase. In
particular, the catalytic hydrodehalogenation of seven aliphatic chlorinated organic
compounds (PCE, TCE, cis-1,2-DCE, 1,1-DCE, 1,1,2,2-TCA, 1,2-DCA), and the
hydrogenation as well as oxidation of ether compounds used as fuel oxygenates
(MTBE, ETBE, TAME, DIPE) was studied over palladium catalysts. In all cases the
compounds were transformed to non toxic or less toxic products. Reaction rates were in
general pseudo first order and half lives were in the range of milliseconds to seconds,
depending on the compound and the temperature. As an example the temperature
dependent first order rates obtained for the reductive conversion of chlorinated aliphatic
compounds are compiled in Table 1. In general, ethane was the sole degradation
product.
Table 1: Gas phase reductive catalytic conversion of chlorinated aliphatic compounds
using a palladium on alumina catalyst. Rates are reported as sec -1 .
T, o C 1,1-DCE c-1,2-DCE TCE PCE 1,1,2,2-
TCA
1,2-DCA Chloroethane
50 9.42±0.09 7.91±0.18 4.23±0.18 3.2±0.04 n.d. n.d. n.d.
75 13.4±0.25 11.8±0.40 7.42±0.12 5.82±0.11 n.d. n.d. n.d.
100 18.9±0.46 18.2±0.25 11.9±0.18 9.83±0.10 4.35±0.09 n.d. n.d.
150 29.4±0.54 28.9±0.63 21.8±0.48 19.4±0.25 12.3±0.12 n.d. n.d.
200 n.d. n.d. 38.2±1.35 36.8±0.69 24.2±0.27 1.50±0.05 n.d.
250 n.d. n.d. n.d. n.d. 39.9±0.25 3.14±0.04 2.55±0.06
300 n.d. n.d. n.d. n.d. n.d. 6.13±0.06 5.26±0.15
350 n.d. n.d. n.d. n.d. n.d. 9.48±0.13 9.05±0.11
400 n.d. n.d. n.d. n.d. n.d. n.d. 15.5±0.26
Currently, a container based pilot scale groundwater treatment plant is under
construction in cooperation with the Environmental Research Center Leipzig/Halle
(UFZ) to advance this technology into real use.
- 143 -

Diffusion and reaction in micro- and mesopores
Christoph Schüth
Diffusion in micro- and mesopores is in many cases limiting for mass transfer and
reaction rates in porous natural or synthetic materials. Accessibility and reactivity of
micro- and meso-pore domains should be a function of the pore sizes as well as pore
polarities. In natural po-rous media both parameters can be assumed to show a
distribution, depending on the type of the porous material. Moreover, educts and
products of a reaction may show different po-larities resulting in a distribution of
diffusivities with an impact on overall reaction rates.
The objective of this work is the synthesis and characterization of well-defined porous
mate-rials with different pore sizes and polarities containing catalytically active sites,
and study their accessibility with various methods. The catalytic hydrodehalogenation of
chlorinated hydrocarbons (trichloroethylene (TCE) and chlorobenzene) and the
hydrogenation of ben-zene serve as model reactions resulting in different product
distributions in terms of polarity and molecular size. The use of well-characterized
model solids should allow to relate diffu-sion rates and reactivities of the different
materials to pore sizes and pore polarities.
In the first step, the synthesis and first characterization of metal complexes will be
performed. The selection of the metal complexes is predefined by the model reactions
as described earlier. Pincer complexes (M-1a-c,2a-c) which are accessible by various
procedures will be synthesized. In general a number of organic and organometallic
transformations have to be performed to generate complexes M-1a-c,2a-c. Their special
features are the different donor atoms which coordinate to the metal, the functional
groups at the donor atoms and very important for this project the hydrolysable group at
the end of the spacer. These features allow to adjust the metal complexes for a special
application in catalysis.
(R'O) 3Si
X
[M]
X
M-1a-c, M-2a-c
Scheme 1
X = SR (1), NR 2 (2)
R = Me (a), Ph (b), Cy (c)
[M] = Rh, Pd, Ni, Ru complex fragments
R' = Me, Et
Spacer e.g. C 6-alkane or short PEG chain
It is planned to perform the dehalogenation reactions with the SCS-Pd complexes (Pd-
1). Catalysts of this type are highly stable in air and water and are known to cleave
carbon-chlorine bonds. This will be important for field applications planned at a later
date of this project. To fine tune the active center with respect to electron density and
steric hindrance R will be varied from methyl (Pd-1a), phenyl (Pd-1b) to cyclo-hexyl (Pd-
1a). All complexes will be screened for their catalytic activity in dehalogenation and
hydrogenation reactions.
- 144 -

Those complexes which performed best in the reactivity screening will be incorporated
into porous oxides. The porous oxides will be prepared by sol-gel processing. This
technique allows the creation of oxide networks by progressive hydrolysis and
condensation reactions of molecular precursors (Scheme 2). Therefore it is an ideal and
versatile method to incorporate well defined metal complex catalysts into the network.
The parameters which influence the sol-gel reaction allow to control the morphology and
properties of the materials. As in this project the pore size and the polarity of the matrix
are of interest only those parameters will be varied which have an influence on this
properties.
The following educts and parameters will be considered: (1) The alkoxysilanes
tetramethoxysilane (TMOS), tetraethoxysilane (TEOS), methyltrimethoxysilane
(MTMOS) and phenyltrialkoxysilane (PhTMOS); (2) The metal complex catalysts
developed; (3) the solvents THF, H2O, ethanol, ethylene glycol, glycerine; (4) pH; (5)
templates (tensides, organic polymers etc.).
k H 2O +
l Si(OR') 4 +
m RSi(OR') 3 + n
Scheme 2
(R'O) 3Si
1. pH
X 2. Solvent
3. Templates
[M]
4. Temperature
5. Pressure
X
6. Stirring speed
M-1a-c,2a-c
MOS and TEOS are network builders. Their different alkoxy groups allow to control the
ki-netic of the hydrolysis. If only these are used in the reaction the pore size of the
materials depends on the pH. The amount of alkyltrimethoxysilanes will have an
influence on the pore sizes and on the polarity. It is further assumed that the Alkyl group
will have an additional effect on the diffusion of the organic molecules into the porous
material. For the generation of larger pore sizes template additives might have to be
used. Due to the thermal sensitivity of the metal complexes calcination has to be
excluded. Thus the additives will have to be ex-tracted by extensive solvent processing.
During the mixing of the organic and inorganic reaction partners the organic part of the
metal complex catalyst will be surrounded by the non-polar organic functions R. This will
ensure that in the final material the catalyst will be on the non-polar surface of the
pores.
When the main properties of the solids and the resulting processes limiting or enabling
the access of diffusing compounds into micro- and mesopores are known, this
knowledge could be used to synthesize tailored materials for a specific application. This
could be catalysts with high and sustained reactivities in aqueous systems by
selectively providing access to reactive sites. In groundwater remediation, there is
especially a need for destructive methods as can be achieved by catalysis, because no
secondary waste streams are produced. Besides the fundamental research, this project
has therefore also a very applied background, with the potential for a commercial
utilization of the results.
- 145 -
Si
X
X
[M]
X

Rift dynamics, uplift and climate change in
Equatorial Africa:
Sybille Roller, Matthias Hinderer, Jens Hornung
Situated in the central western branch of the East African Rift system, the Rwenzori
Mountains and adjacent rift flanks are the highest uplifted rift flanks on earth. Their
extreme uplift may have significantly contributed to the aridisation of East Africa since
the Late Miocene.
Within the DFG research Unit (Forschergruppe “RIFTLINK” with University of Frankfurt,
University of Mainz and other institutions) we are running the sedimentological part
which is titled:
Linking source and sink in the Rwenzori Mountains and adjacent rift basins,
Uganda: landscape evolution and the sedimentary record of extreme uplift
The goal of the subproject is to study the erosional denudation of the Rwenzori
Mountains since their extreme uplift in the Late Miocene. This comprises both, analysis
of the erosional features and landscape evolution, as well as the sedimentary record in
the adjacent rift basins. The working programme for the running time of the project is
based on three investigation fields: 1.) “Source region”: Erosion and fluvial transport, 2.)
“Sink region”: Basin analysis, 3.) “Modelling”: Numerical simulations of landscape
evolution including basin fill history.
Prevailing questions concern the close connection between the extreme uplift and the
erosive unloading and the chronological relation of both processes. Therefore, we try to
understand the role of endogenic processes, the role of climate, and the possibility of a
dynamic balance between uplift and denudation. We intend to develop a timestratigraphic
frame from the Late Miocene to Present. Moreover we will calculate
denudation rates, sediment efflux, and interpret the controlling factors of both
processes.
Dense tropical vegetation and thick pedogenesis to a certain extent hamper continuous
and area-wide sedimentological investigations, but some scarcely available outcrops
provide insights both in the lake and river sediments and into several of the uplift
induced alluvial fan deposits, respectively, and admit some relative age assumptions, as
well as examinations of lithology, structure, and facies-type. Ages of younger alluvial
sediments are determined using Optically Stimulated Luminescence (OSL) dating.
Erosion rates are evaluated by measuring the concentration of in-situ produced
Terrigenic Cosmogenic Nuclides (TCN; e.g. 10 Be) in the quartz grains of river sands.
The results will then be integrated into an evolutionary model of erosion, sediment flux,
and rift basin fill for the central western branch of the East African Rift.
A first field campaign was carried out in August 2006 to get an idea about the quantity
and quality of the loosely distributed outcrops. For a complete data set of erosion rates,
quartz-bearing river sand was sampled in 14 prominent rivers all around the Rwenzori
Mountains on Ugandan territory. In the meantime the material entered its complex
preparation process for concentration measurement of 10 Be in the accelerator mass
- 146 -

spectrometer (AMS) (method performed in cooperation with University of Hannover and
AMS-Laboratory in Glasgow).
During a second field campaign in January/February 2007 several stratigraphic sections
in the Semliki, Bundibugyo, Mobuku, and Kasese areas were mapped in detail to
resolve the temporal and spatial relationship between lake sediments, distal floodplain
sediments, and proximal alluvial fan deposits. Interfingering is complex due to
contemporaneous influence of both fluctuating climatic and tectonic events. At key
localities and if lithology was appropriate, lightproof samples for OSL-dating were
excavated. Comparable to TCN-dating, the OSL-method requires highly sophisticated
preparation and measurement performance that can be provided by the OSL lab at
Liverpool University.
A high-resolution DEM (30m) helps to analyse the landscape morphometry of the rift
flanks. Beside a visual interpretation of the DEM, ArcGIS helps to quantify the
morphometric parameters (catchment size, hydrological properties).
Fig. 1: High resolution DEM of the Rwenzori Mountains situated in the western branch of the
East African Rift system.
- 147 -

Geology, land use change and erosion in the northern
periphery of Belo Horizonte, Brazil
Monika Hofmann 1 , Andreas Hoppe 1 , Allan Buchi², Joachim Karfunkel 2,
Ricardo Pagung 2
1 Institut für Angewandte Geowissenschaften, TU-Darmstadt, Germany;
2 Instituto de Geociências, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
Belo Horizonte, the capital of the state Minas Gerais (Brazil), has been considered by
the UNO as one of the cities of South America that will be a megacity with more than
ten million inhabitants by the middle of this century. As the city already does not support
its growth to the south because of restricted access and accentuated relief, the future
tendency will be to expand towards the north. The newly built highway between the
international airport Confins 40 km north of Belo Horizonte and the city itself is
accelerating the urbanization of the neighbouring municipalities, especially as tax
reductions for industrial plants and easy access are favouring rapid development of the
region. The urbanized area, including the area in process of urbanization (periurban
area / bare soil), increased from 13% in 1987 to 20 % in 2002. In the same time, the
forested area decreased from 45 to 36%. The analysis of geo-resources and geohazards
is essential for the sustainable growth of every city, even more so if the city is
growing very fast into a fragile environment as is the case in Belo Horizonte.
Lagoa Santa, a city of 45000 inhabitants lying at the triangular lake north of Belo
Horizonte, is the biggest city affected by the trend towards urbanisation due to the new
highway. The prices for real estates in its municipal area are rising even before the
highway is finished. Still, Lagoa Santa is situated on highly erodible siltite hills and
severe erosion with has formed many gullies is already threatening the infrastructure.
Also in the neighbouring valley of the Riberão da Mata whose alluvial plain serves both
as sand, clay and gravel resource and as one of the very few plain building sites,
concentrated overland flow resulting from sealed areas increase the risk of inundations.
Fig. 1: Belo Horizonte and the study site in its northern periphery.
In the whole northern periphery of Belo Horizonte which includes the municipality of
Lagoa Santa, a general erosion index has been calculated, regarding the erodibility of
soils as well as topography: The erodibility of soils has been estimated on behalf of the
lithology in the area and whether laterite crusts exist or not. While the Archean
- 148 -

granite/gneiss basement rocks in the south and west are highly erodible due to deep
weathering and low infiltration capacity, the overlying carbonate rocks outcropping in the
north and east are less prone to erosion due to better soil structure and rapid infiltration
in the karst system which prevents excessive overland flow (Fig. 2). Around the lake of
Lagoa Santa, the Neoproterozoic carbonate rocks are overlain by siltite rocks with a
very low infiltration capacity and weak soil and saprolite cohesion. In these highly
vulnerable hills, many gullies can be observed already, most but not all of them related
to urban areas. On the mountain tops in the middle of the study area, laterite crusts
protect the underlying soils from erosion and thus these areas are assigned low
erodibility values.
Fig. 2: Erosivity of the study area, based on
lithology and the existence of laterite crusts.
Fig. 3: Erosion hazard of the study area
derived by overlay of erosivity and topographic
index.
- 149 -
A map showing the natural erosion
hazard in the area has been created
by overlying the erodibility map with a
map showing a topographic index
based on the length slope factor used
in the universal soil loss equation. The
resulting map (Fig. 3) highlights the
areas of the steep siltite hills around
the city of Lagoa Santa in the east and
the hilly landscape on Archean
gneiss/granite rocks in the south and
west. In an ongoing study existing
gullies in Lagoa Santa are evaluated
with regard to their catchment area,
steepness, flow concentration along
roads and the amount of sealed area
in the catchment in order to estimate
local threshold values for gullying.
Additionally to regional erosion hazard
estimation, a local case study on land
use change due to sand and gravel
extraction and urbanisation in the
alluvium of the Riberão da Mata has
been performed. This area has been
subject to sand, clay and gravel
extraction during the last decades, and
many of the small scale mining sites
have been simply left open after the
extraction had been banned due to the
Brazilian legislation that puts a buffer
zone along rivers under protection or
as sand extraction at low costs above
the groundwater level was not viable
anymore. Still, it is one of the few
areas close to the city where sand and
gravel for construction purposes can
be found. A visual analysis of aerial
photos and satellite images covering

nearly half a century has been performed, concentrating on the impact of sand and
gravel mining and the recuperation of abandoned mining areas as well as on the
proceeding urbanisation. Fig. 4 shows the dynamic of the urbanisation of the alluvial
plains from 1977 until 1990. These analyses were accompanied by field observations
including geological, pedological and environmental aspects such as the state of the
recuperation of abandoned extraction areas as well as sedimentological structures. The
total area of 6,68 km² of the alluvium between the road MG 424 and the road MG 010,
have been subject to many drastic transformations during the last decades. Frequent
changes of the riverbed, erosion at its margins, siltation and the augmentation of
exposed soil in the alluvial plain could be observed.
Fig.4: Proceeding urbanisation of the alluvial plain of the Riberâo da Mata
between 1977 and 1990.
The peak of the sand mining activities was in the decades of 1970 to 1980, when the
city of Belo Horizonte was growing very rapidly and environment legislation was less
strict. Still, even today, active sand and clay mines can be found in the area, showing
the importance of these resources for the city. During the last decades, approximately
30% of the study area has been subject to mining (1.5 km² during the 1977 and only 0,5
km² in 1990). In some abandoned mining areas, industrial plants breaking carbonate
rocks for gravel substitution have been constructed, as the alluvium offers plain
construction sites. The gravel mining has stopped since, as the natural gravel resources
are scarce and deep seated. The natural recuperation of abandoned mining areas is
slow and exposed soil and active erosion carries away fertile soil and increases the
sediment load of the river. In the 1970s, 0,4 km² of the area could be classified as
exposed soil showing signs of erosion. The multi-temporal analysis of the land use in
this area together with a comparison with other source areas showed that certain georesources
like sand and gravel for construction purposes are heavily needed in close
distance to the growing city, but competing for space with other uses and with
environmental legislation.
- 150 -

Planar Defects in Bixbyite, (Mn,Fe)2O3;
A Prominent Diffusion Path
Hans-Joachim Kleebe, Stefan Lauterbach
Bixbyite is a rather uncommon manganese-iron oxide (Mn,Fe)2O3, crystallizing in the
Ia3 space group [1], forming black cubic crystals with metallic lustre that are commonly
truncated by small icositetrahedral faces at corners. Bixbyite normally occurs in small
crystals reaching some mm in size. However, there is one location at Thomas Range
(Utah), where large crystals up to 4 cm are found. These crystals occur in cavities of a
rhyolite host rock associated with topaz, pseudobrookite, braunite, hematite,
hausmannite and quartz [2].
In contrast to the small isomorphic crystals, most of the larger bixbyite crystals from
Thomas Range show distinct re-entrant facets at halfway of every edge of the cube,
linked by a band of parallel linear features, crossing at the center of each cube face.
These linear features were first characterized as twin boundaries, but they cannot be a
result of local twinning, since any twinning operation on {100} planes of the
centrosymmetric bixbyite structure would produce an identical single crystal.
High-resolution transmission electron microscopy (HRTEM) was used to study the
structure of those linear features. HRTEM images showed fault planes running along
{100} planes of the bixbyite structure. The interfaces are atomically sharp and planar
over large areas of the crystal. TEM/EDS analyses revealed an enrichment of Si in the
fault regions with a simultaneous increase in Mn. The composition of the planar defects
closely corresponds to the manganese silicate braunite, Mn 2+ Mn 3+ 6SiO12 [3].
Small precipitates observed in close proximity to the planar faults suggest an increased
diffusion rate along those defects. The enhanced grain growth of the larger bixbyite
crystals can be rationalized by fast diffusion along those planar braunite interlayers.
[1] Dachs, H. (1956): Die Kristallstruktur des Bixbyits (Fe, Mn)2O3, Z. für Kristallographie, 107, 370.
[2] Eric H. Christiansen, E. H, James V. Bikun, J. V., Michael F. Sheridan, M. F., Donald M. Burt, D. M.
(1984): Geochemical Evolution of Topaz Rhyolites from the Thomas Range and Spor Mountain, Utah,
American Mineralogist, 69, 223.
[3] De Villiers, J.P.R. & Buseck, P.R. (1989): Stacking Variations and Non-Stoichiometry in the Bixbyite-
Braunite Polysomatic Mineral Group, American Mineralogist, 74, 1325.
- 151 -
Fig. 1: HRTEM image of the intrinsic defect
structure observed in a lager bixbyite single
crystal. Note the presence of small
precipitates adjacent to the planar faults of
braunite, Mn7SiO12.

The Effect of LiF Addition on the Sintering Mechanism of
Spinel, MgAl2O4
Hans-Joachim Kleebe, Mathis Müller, Keith Rozenberg 1 , Ivar E. Reimanis 1
1 Colorado School of Mines, Metallurgical and Materials Engineering Dept., Golden, CO 80401, USA
MgAl2O4 is widely regarded as one of the most promising optical ceramics [1,2]. It has
excellent transmissivity in the near infrared frequency range. There is an excellent body
of research on the sintering mechanisms of pure spinel for optical applications.
Unfortunately hot pressing with LiF doped spinel, which is one of the most promising
processes for producing optical quality spinel ceramic, is also one of the least
understood. Many compounds have been proposed or used as sintering aids for
MgAl2O4 spinel (hereafter called spinel). For example, Na3AlF6, AlCl3, CaCO3, and LiF
have all been shown to promote sintering in spinel, though the detailed mechanisms
have remained elusive. LiF has been used to speed up the sintering kinetics of several
other systems including SrTiO3, and BaTiO3, and MgO. LiF, is the only compound
considered for use as a sintering aid in the production of low porosity, transparent spinel
via hot pressing.
The effect of LiF on the sintering of spinel has been only qualitatively studied. An
understanding of the mechanism for removal of LiF from the system is essential as any
residual LiF or related species could destroy the optical properties of the material. It has
been shown that LiF reduces the sintering temperature of spinel by nearly 200°C, and
decreases reaction temperatures during reactive sintering. More recent studies on
dense spinel were performed to determine the location of LiF subsequent to sintering,
with the objective of better understanding its role in sintering. LiF was not identified in
any of the studies, suggesting that it may react with spinel during sintering and/or
ultimately was removed from the system. It is known that LiF is active at the interface
between spinel grains at higher temperatures. Furthermore, it has been reported that
spinel sintered in the presence of LiF has a substantially higher Al content. Large
amounts of LiF have also been observed to act corrosively with spinel. All of these
observations indicate that LiF does chemically react with the spinel at elevated
temperatures. A recent study indicates that LiF reacts with Al in spinel, forming LiAlO2,
and leaving Mg-rich regions in the matrix. This, however, leaves the question of what
becomes of the fluoride species. This spinel
project addresses the issue of how LiF can
promote the sintering performance of
magnesium aluminate. In addition to HRTEM
investigations, model experiments with high
volume fraction of LiF addition are performed.
[1] R. J. Bratton, “Translucent Sintered MgAl2O4”,
J. Am. Ceram. Soc., 57 [7] 283-86 (1974).
[2] C.-J. Ting and H.-Y. Lu, “Hot Pressing of
Magnesium Aluminate Spinel; Part-II. Microstructural
Development”, Acta mater. 47 [3] 831-
40 (1999).
Fig. 2: TEM image of the spinel sample, doped
with 5 wt% LiF and pre-sintered at 900 o C. In close
proximity of the intrinsic pores, an amorphous LiFphase
was observed (transient phase).
- 152 -

Microstructure Characterization of Boron Suboxide, B6O
Hans-Joachim Kleebe, Stefan Lauterbach, Mathias Herrmann 1 ,
Jack Sigalas 2
1 Fraunhofer Institut für Keramische Technologien und Systeme, Dresden
2 University of the Witwatersrand, Johannesburg, Gauteng, South Africa
Hexaboron monoxide (B6O), commonly termed boron suboxide, is known as a
superhard material, constituted of the light elements boron and oxygen. The
extraordinary hardness of such a low-density material has been attributed to the intrinsic
strong and directional covalent bonds between B and O, leading to a tight, threedimensional
network with an excellent resistance towards external shear.
The average Vickers hardness (Hv) of B6O is about 45 GPa, which is next to diamond
(Hv: 70–100 GPa) and cubic boron nitride, c-BN (Hv: 45–50 GPa). Similarly, the
average fracture toughness of B6O (4.5 MPa m 1/2 ) is higher as compared to c-BN (2.8
MPa m 1/2 ) and comparable to diamond (5.0 MPa m 1/2 ). Due to its strong covalent
bonding, B6O materials demonstrate exceptional physical and chemical performance
such as high hardness, low density, high thermal conductivity, chemical inertness and
good wear resistance. Its thermal stability, even at temperatures above 1000 °C, and
its chemical inertness with ferrous alloys makes it in some instances even more suitable
for industrial applications as for example diamond. In general, B6O materials have
potential applications as abrasives, due to their high hardness, and are also considered
as potential candidates for high-temperature semiconductors (with an estimated band
gap of approximately 2.4 eV) and for
thermo-electrics. Despite various potential
applications, densification and processing
of B6O materials was shown to be rather
cumbersome. Therefore, a detailed
microstructure characterization was
performed in order to gain insight in the
submicron structure that formed upon
sintering.
ACerS – NIST Phase Equilibria Diagrams
Fig. 02339—System Al2O3-B2O3.
P. J. M. Gielisse and W. R. Foster, Nature
(London), 195 [4836] 69-70 (1962).
The main objectives of the TEM study were
(i) to verify as to whether an amorphous
intergranular phase is present at the B6O
grain boundaries (doped versus undoped
sintered samples), (ii) what type of
crystalline grain-boundary phases are
present in the sintered, coated B6O sample:
Al4B2O9 and/or Al18B4O33, and (iii) the
overall defect structure in the materials was
to be characterized (in particular, the
question whether stacking faults in B6O can
be eliminated via long-term annealing was
addressed).
- 153 -

In case of the undoped sintered B6O sample, the individual B6O grains are typically well
faceted with sharp edges. The grain-size distribution in this sample is bimodal with
larger grains (1-2 µm) embedded in a fine-grain B6O matrix. All B6O grains typically
reveal numerous stacking faults (similar to B4C particles). In the case of the doped,
sintered B6O sample, the grain size was greatly increased (by a factor of about 5x).
Stacking faults are a common feature of this B6O material even upon long-term anneal.
A secondary phase formation was observed in the Al-containing sample. With respect to
the phase diagram, the two aluminium borate compounds that are most likely to form
upon sintering are Al4B2O9 and/or Al18B4O33.
Conventional TEM (bright field; Figure 3) and HRTEM (Figure 4) were performed on the
crystalline secondary phase in addition to selected area electron diffraction (SAD). The
diffraction pattern given in Figure 4 can be indexed corresponding to a primitive
orthorhombic unit cell (a,b = 0.7617 and c = 0.2827 nm; Pbma) as well as with respect
to an A-centered orthorhombic symmetry (Amam). EDS analysis does not allow the
distinction between both phases, because this technique is rather insensitive to boron
(no quantitative analysis possible). The A-centered phase; however, should follow the
extinction rules (k+l=2n). Under the assumption that the rather weak {010}-type
reflections visible in the SAD-pattern
(Figure 4) are a result from 2 nd -order Laue
reflections, it is concluded that extinction
occurs. Therefore, the secondary crystalline
Al-compound observed in this material is
the Al18B4O33 phase. It should be noted that
the secondary phase shows an identical
orientation within an area of 20-50 microns
within the sample. This observation
indicates that this Al-phase is characterized
by a rather low nucleation rate, which is
uncommon for most secondary phases.
Fig. 3: TEM image of the secondary Al-phase,
Al18B4O33, observed in the doped, sintered B6O
sample.
Fig. 4: HRTEM image of the secondary Alphase
present in B6O. Note the presence of
stacking faults as well the weak reflections in
the SAD pattern (extinction).
- 154 -

Pressure and Temperature Dependence of the Fe 2+ /Fe 3+ -Ratio
in Omphacite for the Re-Calibration of the Fe-Mg
Geothermometer
Stefan Lauterbach, Hans-Joachim Kleebe
Iron is present in omphacite, (Ca,Na)(Mg,,Al,Fe 2+ ,Fe 3+ )Si2O6, a common clinopyroxene
(Figure 5), as di- and trivalent cations. Analyzing the iron content via micoprobe, the
overall iron content can be determined; however, without a distinction between Fe 2+ and
Fe 3+ . The commonly used geothermomenter calibration of high pressure (HP) and ultrahigh
pressure (UHP) eclogites is solely based on the Fe 2+ content as the total iron
content. Thereby, the determined corresponding formation temperatures may differ by
up to 400 degree Celsius, since the Fe 3+ content is not considered.
Mathematical corrections of the Fe 2+ /Fe 3+ -ratio in omphacite are based on stoiciometric
considerations, while analytical techniques to determine the actutal Fe 3+ content are still
lacking. Moreover, experimental calibration of the Fe 2+ /Fe 3+ -ratio are commonly not
satisfying. Therefore, a re-calibration of the Fe 2+ /Fe 3+ -ratio is performed by measuring
both the Fe 2+ and Fe 3+ content in omphacite employing the technique of electron
energy-loss spectroscopy (EELS). Parallel, energy-dispersive X-ray spectroscopy
(EDS) is used, in order to determine the overall Fe-content of the sample. The
experimental EDS and EELS data allow a quantitative determination of the Fe 2+ and
Fe 3+ content. In addition, the high lateral resolution of the transmission electron
microscope (TEM), down to a few nanometer, allows the analysis of model samples that
were synthesized at rather low temperatures (short diffusion profile), which are close to
the formation temperature assumed for natural omphacites.
Due to the high lateral resolution of the electron transmission microscopy techniques
EELS and EDS, exchange equilibria at the sub-micron level are suitable for the
experimental determination of the Fe 2+ /Fe 3+ -ratio, even at synthesis temperatures as
low as 800 o C. Such low-temperature samples omit the normally applies extrapolation of
HT data to low temperatures and add “hard data” to the lower temperature regime.
Apart from synthetic samples, natural omphacites (HP-eclogites) from the Tauern
Window are studied.
Fig. 5: TEM bright field image of Omphacite,
(Ca,Na)(Mg,,Al,Fe 2+ ,Fe 3+ )Si2O6; clinopyroxene)
in an orientation which reveals typical antiphase
boundaries (APB; courtesy W. Müller).
- 155 -

Microstructures in Omphacite and Other Minerals from
Eclogite Near to the Interface Eclogite Zone/Lower Schist
Cover, Tauern Window, Austria
Wolfgang Friedrich Müller and Gerhard Franz 1
1 Institut für Angewandte Geowissenschaften, Technische Universität Berlin
Rapid exhumation of eclogitic rocks from depths between 60 and 100 km to an
intermediate crustal level of about 30 km or less, is frequently reported from high- and
ultra-high pressure terrains. It is unclear, however, how the rocks and their mineral
constituents respond to such high strain rates, which are possibly also associated with
large, crustal earthquakes. It is also an open question, which mechanical and
temperature effects are produced by fast exhumation of high-pressure nappes or
intercalated slices in its neighbourhood and in itself.
It was recently established [1] that the high-pressure terrain of the Pennine in the
Eastern Alps, the Eclogite Zone (EZ) in the Tauern Window, shows very high uplift
rates. Radiometric age determinations (Rb/Sr) from eclogite facies rocks of the EZ and
of post-eclogitic greenschist facies vein assemblage revealed minimum uplift rates of >
36 mm/a. The event of the rapid imbrication of the EZ between other tectonic units
caused unusual deformation microstructures in a sample from the lower tectonic unit
which is the Venediger nappe or Lower Schist Cover (LSC) [2]. In an eclogite sample on
the order of 10 m distant from the EZ polygonisation of garnet into subgrains of 0.5 to 3
µm, high dislocation density in titanite, and deformation twin lamellae on (100) in
clinozoisite were observed [2]. In order to see if there are similar effects in rocks from
the EZ, we studied an eclogite as close as possible to the thrust plane by transmission
electron microscopy (TEM). The distance of the sample locality to the thrust fault
between LSC and EZ is about 50 m. This sample (WP 291) served already Glodny et al.
[1] for the age determination. According to thermobarometry, the EZ eclogites have
experienced peak P-T conditions of 2.0 - 2.5 GPa and 600 ± 30 °C (see [1] and
quotations therein).
Omphacite
The omphacite grains impress by their wealth of microstructures: Antiphase domains
(APDs) separated from each other by antiphase domain boundaries (APBs), chain
multiplicity faults (CMFs), twin lamellae on (100), non-crystallographic faults, free
dislocations, small angle grain boundaries, and recrystallised grains. With exception of
the APDs, all microstructures are due to deformation and to recovery and
recrystallisation as consequence of deformation which may be syn- or
postdeformational.
Antiphase domains (APDs) are present in all grains studied. They arise from the phase
transition C2/c→P2/n due to the diffusion-controlled ordering of Mg and Al. The
displacement vector of the antiphase domains is 1/2[110] [3, 4]. From the peak
metamorphic temperature of the EZ of about 600 °C it is clear that our omphacite
crystallised first in the disordered C-lattice but within the phase regime of the P-phase
[3]. The APDs have mostly a size of 0.2 to 0.4 µm. Electron diffraction patterns show
well-ordered omphacite of space group P2/n with sharp reflections.
CMFs (intercalations of layers with a different chain multiplicity; here double chains like
in amphibole) parallel to (010) are frequenty observed. They have been described in
- 156 -

detail by [5]. CMFs are apparently quite typical for omphacites from the EZ and the LSC
from the Tauern Window, and are seldom described from other occurrences.
An astonishing feature observed in several omphacite grains are faults which are not
oriented parallel to a distinct crystallographic plane but have preferential orientations
subparallel to (100); they are terminated by dislocations. These ‘non-crystallographic
faults’ were apparently produced by moving dislocations. Attempts to analyze their
displacement vector failed.
While free dislocations are rare, small-angle grain boundaries formed by one or two sets
of dislocations are relatively frequent. In one case, even a recrystallizing grain was
observed (Fig. 1a) forming a large angle grain boundary with the matrix grain.
Polysynthetic twin lamellae on (100) (Fig.1b) are interpreted as deformation twins
because growth twins of this type are unknown and the grain is obviously deformed as
evidenced by free dislocations.
Clinozoisite shows deformation twin lamellae on (100) with widths which vary between
about 3 and 150 nm. They have been first observed in the LSC sample close to the
interface to the EZ [2]. Garnet contained rarely dislocations and low angle grain
boundaries. Barroisitic amphibole displayed a small-angle grain boundary which
consisted of segments parallel to (110), but otherwise no specific deformation effects
were apparent.
In conclusion: The TEM results show strong deformation of omphacite and clinozoisite,
but garnet is almost free of dislocations. Comparison of these results with those by
Barnert [6] on samples farther away from the interface to the LSC shows no significant
differences of the effects of ‘normal’ deformation in the EZ omphacites and the
deformation associated with the rapid exhumation. The only exception are the noncrystallographic
faults in omphacite mentioned above which may indicate locally
elevated temperatures.
Fig.6: TEM electron micrographs of omphacite. (a) Recrystallising grain (bright grain in the left
corner) growing into the omphacite matrix in which APBs are visible; bright-field image. (b)
Omphacite with deformation twin lamellae on (100); dark-field image.
[1] Glodny J. et al. (2005) Contr. Mineral. Petrol. 149, 699-712
[2] Müller W.F., Franz G. (2004) Eur. J. Min. 16, 939-944
[3] Champness P.E. (1973) Am. Mineral. 58, 540-542
[4] Phakey P.P., Ghose S. (1973): Contr. Mineral. Petrol. 39, 239-245
[5] Müller, W.F. et al. (2004) Eur. J. Min., 16: 37-48
[6] Barnert, E.B. (2003) Doctoral thesis, TU Darmstadt, Fb 11
- 157 -

Modelling phase-assemblage diagrams for magnesian
metapelites in the system K2O – FeO – MgO – Al2O3 – SiO2 –
H2O: geodynamic consequences for the Monte Rosa nappe,
Western Alps.
R. Le Bayon 1 , C. de Capitani and M. Frey 2
1 TU Darmstadt and 2 University of Basel, CH
Magnesian metamorphic rocks with metapelitic mineral assemblages and composition
are of great interest in metamorphic petrology for their ability to constrain P-T conditions
in terranes where metamorphism is not easily visible. Phase-assemblages diagrams for
natural and modal magnesian metapelites in the system KFMASH are presented to
document how phase relationships respond to water activity, bulk composition, pressure
and temperature. The phase assemblage displayed on these phase diagrams are
consistent with natural mineral assemblages occurring in magnesian metapelites. It is
shown that the equilibrium assemblages at high pressure conditions are very sensitive
to a(H2O). Specifically, the appearance of the characteristic HP assemblage chloritoidtalc-phengite-quartz
(with excess H2O) in the magnesian metapelites of the Monte Rosa
nappe (Western Alps) is due to reduction of a(H2O). Furthermore, the mineral
assemblages are determined by the whole-rock FeO/(FeO+MgO) ratio and effective Al
content XA as well as P and T.
The predicted mineral association for the low- and high –XA model bulk compositions of
magnesian metapelites at high pressure are not dependent on the XA variations as they
show a similar sequence of mineral assemblages. Above 20 kbar, the prograde
sequence of assemblages associated with phengite (with excess SiO2 and H2O) for low-
and high-XA bulk compositions of magnesian metapelites is: carpholite-chlorite –»
chlorite-chloritoid –» chloritoid-talc –» chloritoid-talc-kyanite –» talc-garnet-kyanite –»
garnet-kyanite ± biotite. At low to medium P-T conditions, a low-XA stabilises the
phengite-bearing assemblages associated with chlorite, chlorite + K-feldspar and
chlorite + biotite while a high-XA results in the chlorite-phengite bearing assemblages
associated with pyrophyllite, andalusite, kyanite and carpholite. At high-XA magnesian
metapelites with nearly iron-free content stabilises the talc-kyanite-phengite assemblage
at moderate to high P-T conditions.
Taking into account the effective bulk composition and a(H2O) involved in the
metamorphic history, the calculated phase-assemblage diagrams may be applied to all
magnesian metapelites that have compositions within the system KFMASH and
therefore may contribute to gaining insights into the metamorphic evolution of deep
buried structural units. As an example, the magnesian metapelites of the Monte Rosa
nappe have been investigated, and an exhumation path (following Alpine continental
collision of the subdued delaminated Monte Rosa nappe) with P-T conditions for the
western roof of the Monte Rosa nappe has been derived for the first time. The
exhumation shows first a near-isothermal decompression from the Alpine eclogite peak
conditions around 24 kbar and 505°C down to approximately 8 kbar and 475°C followed
by a second decompression with concomitant cooling.
- 158 -

Chemical composition and mineralogical composition of
Saharan mineral dust over south east Morocco
K. Kandler 1 , C. Deutscher 2 , M. Ebert 1 , H. Hofmann 1 , S. Jäckel 1 , A.
Petzold 3 , L. Schütz 2 , S. Weinbruch 1 , B. Weinzierl 3 , S. Zorn 2
1 Institute of Applied Geosciences, Darmstadt University of Technology, Darmstadt
2 Institute for Physics of the Atmosphere, Johannes-Gutenberg-University, Mainz
3 Institute of Atmospheric Physics, German Aerospace Center, Wessling
The Saharan Mineral Dust Experiment (SAMUM) is dedicated to the understanding of
the radiative effects of mineral dust. A joint field campaign focussed on the source-near
investigation of Saharan dust was carried out in southern Morocco. Ground based
measurements were a performed near Tinfou and at the Ouarzazate airport; airborne
measurements were carried out onboard a Falcon and a Partenvia aircraft. Together
th th
with Satellite observations, these measurements ranged from May 13 to June 7 , 2006.
Airborne as well as ground based samples were collected with a miniature impactor
system on carbon coated substrates and carbon foils; additionally, filter samples were
collected, of which the aerosol mass concentration was determined. The size-resolved
particle aspect ratio and chemical composition is determined by means of electronmicroscopical
single particle analysis. The mineralogical composition of the filter
samples is determined by x-ray diffraction. Additional information on single particles will
be collected by transmission electron microscopy.
The bulk mineralogical composition was found to be dominated by major compounds
like quartz, calcite, feldspars (plagioclase and K-spars), and clay minerals
(illite/muscovite, kaoline, and chlorite) and minor compounds like hematite.
relative fraction
1.0
0.8
0.6
0.4
0.2
n=50 n=361 n=1276 n=1329 n=209 n=13
0.0
1 10
particle diameter, µm
other
carbonaceous
sulfates
mixtures
silicates
quartz
halite
gypsum
other calcium rich
carbonates
titanium rich
iron rich
Fig. 1: Relative abundance of particles classes as function of particle diameter for a sample
collected at 100 m altitude above the valley east of Ouarzazate, Morocco
- 159 -

As an example, Fig. 2 shows the chemical composition of particles between 1 and
1.5 µm in diameter as a function of measurement altitude over Tinfou for May 19, 2006,
11:24 to 11:42 h. On this day, the mineral dust layer extended up to approximately 4.5
km. The composition of the layer was quite homogeneous, except the sulfate-silicate
mixtures on the ground and at the top of the layer being more abundant than within. The
latter indicates anthropogeneous influence in the boundary layer as well as in the
tropospheric background. On the other hand, the layer was not homogeneous in the
horizontal as is shown by Fig. 1. 140 km to the north east, a significantly higher content
of calcium-bearing particles can be detected, appearing as a mode around 3 µm
diameter.
elevation, m a. s. l.
5,000
4,000
3,000
2,000
1,000
iron rich
titanium rich
carbonates
other calcium rich
gypsum
halite
0.00 0.20 0.40 0.60 0.80 1.00
relative abundance
quartz
silicates
mixtures
sulfates
carbonaceous
other
Fig. 2: Relative abundance of particle classes as function of altitude over Tinfou, Morocco
- 160 -

Diploma Theses
Keil, Matthias; Entwicklung eines geologischen Modells zur Entstehung von Erdfällen in
Nordhessen; Engineering Geology; Juli 2006.
Naser, Simon Marek; Erkundung von Deichen mit Georadar-Möglichkeiten und
Grenzen; Engineering Geology; April 2006.
Schnitzspan, Anne; Risikoevaluation eines Rutschungsgebietes in Graach an der
Mosel; Engineering Geology; April 2006.
Magister Theses
Witt, Bettina; Stadteilentwicklung als Konzept der Stadtförderung. Vergleichende
Untersuchung zu Notwendigkeit und Umsetzung von Stadtteilförderungsprogrammen
am Beispiel dreier Stadtteile; Geography; March 06
Hartmann, Simone; Neue Konzeptionen in der Planung von Großsiedlungen und
Stadtteilen. Erfahrungen aus Fehlplanungen und Fehlentwicklungen von
Großsiedlungen der 60er Jahre dargestellt am Beispiel Darmstadt Neu-Kranichstein;
Geography; March 06
PhD Theses
Lindstaedt, Tamara; Regionsmarketing und die Bedeutung regionsbezogener Identität -
Der Übergangsbereich der Verdichtungsräume Rhein-Main und Rhein-Neckar als
Beispiel; Geography; October 06
Vester, Barbara ; Feinstaubexposition im urbanen Hintergrundaerosol des Rhein-Main-
Gebietes: Ergebnisse aus Einzelpartikelanalysen; Environmental Mineralogy; July 06
Zeiß (Blau), Tatjana ; Die Struktur sekundärer Versorgungsstandorte im südlichen
Rhein-Main-Gebiet und die modellhafte Entwicklung eines räumlichen
Verteilungsmusters; Geography; October 06
- 161 -

MATERIALS SCIENCE
Physical Metallurgy
Ceramics Group
Electronic Material Properties
Surface Science
Thin Films
Dispersive Solids
Structure Research
Chemical Analytics
Theoretical Materials Science
Materials Modelling
Materials for Renewable Energies
Joint Research Laboratory Nanomaterials
Collaborative Research Center (SFB)
APPLIED GEOSCIENCES
Physical Geology and Global Cycles
Hydrogeology
Engineering Geology
Applied Sedimentology
Georesources and Geohazards
Geomaterials Science
Technical Petrology
Environmental Mineralogy
- 162 -
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