book of abstracts - IM2NP

A B S T R A C T S WEDNESDAY, JUNE 30 N A N O S E A 2 0 1 0
9H50-10H10
Magnetic Fluctuations of Bit Cells in Self-Assembled Magnetic Nanopattern.
1,*Kai Schlage, 1Sebastien Couet, 1Stephan V. Roth, 1Ulla Vainio, 2Rudolf Rüffer
3,1Mottakin M. Abul Kashem, 3Peter Müller-Buschbaum and 1Ralf Röhlsberger
(1DESY, Notkestr. 85, 22607 Hamburg, Germany; 2European Synchrotron Radiation Facility, BP 220, 38043
Grenoble Cedex, France; 3TU München, Physik Department E13, 85747 Garching, Germany)* kai.schlage@desy.de
1 – Introduction
On the way towards ultimate magnetic storage densities, self-organized ordered polymer nanostructures
appear to be very promising templates for the growth of magnetic nanodot arrays covering almost arbitrary
large areas with nanoscopic unit cells down to a few nanometre. It is obvious that the maximum density of
separated magnetic nanodots is limited by the superparamagnetic effect when the moments of the dots
become subject to thermal fluctuations.
2 – Abstract
This limit can be overcome by replacing the dot array by its inverse structure, the antidot array. Tailoring the
magnetic properties of such structures requires a deep knowledge of the interplay between structure,
chemistry and magnetism. Here we apply a new kind of 3D microscopy combining high-resolution x-ray
scattering techniques to track all these key parameters during growth of this self-assembled magnetic
nanostructure. A strong selective 3D wetting of iron on the nanostructured polymer template, the formation
of an ultra-thin single-phase oxide layer in contact to the polymer and a unique transition beyond the
superparamagnetic limit of the resulting iron antidot array are directly observed.
3 – Conclusion
The results are expected to have a high impact on the fabrication process of magnetic nanostructures not only
for fundamental research but also for realization of magnetic data storage devices.
10H50-11H20
Band gap engineering in ZnCdO nanostructures: synthesis, properties and
applications.
A.Yu.Kuznetsov, V.Vishnukanthan, M.Trunk, T.Zhang, A.Azarov, A.Galeckas (Dept
of Physics, University of Olso, P.O.Box 1048 Blindern, NO-0316 Oslo, Norway) andrej.kuznetsov@fys.uio.no
Oxide semiconductors in general and ZnO-based semiconductors in particular have attracted much of
attention on behalf of unique properties having promising applications in advanced electronic and
optoelectronic devices. For example, realizing novel band-to-band absorbers made of reasonably cheap
materials is a challenge in photovoltaics and – highlighting just one of ZnO potentials – band gap
engineering in ZnO-based materials can actually answer this challenge. Indeed, alloying ZnO with CdO
results in a gradual band gap shrinking in the range of 3.3-1.8 eV as a function of Cd content. Moreover,
pure ZnO may be readily synthesized in various forms of nanowires (NWs) and manufacturing of ZnCdO
NWs having a graded concentration/bandgap is interesting to research too.
In the frame of this work we are making a systematic effort to manufacture and study ZnCdO, synthesizing
high quality crystalline samples using metal organic vapor phase epitaxy and targeting both multilayer (ML)
and NW structures. The fundamental result reached so far is in realization of graded ZnCdO ML
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