Third Day Poster Session, 17 June 2010 - NanoTR-VI

P indicating
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P
P curves
P existing
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P and
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Poster Session, Thursday, June 17
Theme F686 - N1123
1
Polyol Synthesis of PVP–MnR3ROR4R Nanocomposite
1
1
2
3
Z. DurmusP P, UA. BaykalUP P*, H. Kavas,P P, M.S. ToprakP
2
PDepartment of Chemistry,P PDepartment of Physics, Fatih University, B.Çekmece, 34500 Istanbul, TurkeyP
3
PFunctional Materials Division, Royal Institute of Technology - KTH, SE-16440 Stockholm, Sweden
Absract- We report on the synthesis of polyvinyl pyrrolidone (PVP)-MnR3ROR4R nanocomposites via a polyol route. The capping of PVP around
MnR3ROR4R nanoparticles was confirmed by FTIR spectroscopy, the interaction being via bridging oxygens of the carbonyl (C=O) and the
nanoparticle surface. Tc and TRBR PVP-MnR3ROR4 Rnanocomposite were observed at 42 K and 28.5 K respectively.
MnR3ROR4R is known to crystallize in the normal spinel
structure with a tetragonal distortion elongated along the c-
axis. Manganese ions are placed in the tetrahedral A-sites
2+
3+
(MnP
P) and octahedral B-sites (MnP
P) [1-4]. The FTIR
spectra of PVP and PVP-MnR3ROR4R nanocomposite are
shown in Fig. 1. It is worth noting that the C=O stretch
-1
band is present at 1660 cmP pure PVP and after
formation of PVP-MnR3ROR4R nanocomposite this stretching
-1
red shifts of ~20 cmP
a strong interaction
between MnR3ROR4R nanoparticles and C=O of PVP host
matrix.
Magnetization (emu/g)
0,3
0,2
0,1
FC (100 Oe)
ZFC
-dM/dT
-dM/dT
FC
0 20 40 60 80
ZFC
% Transmittance (a.u.)
PVP
PVP/Mn 3
O 4
2958
2923
4000 3500 3000 2500 2000 1500 1000 500
Wavenumber (cm -1 )
Figure 1. FTIR
nanocomposite.
2882
2855
In plane C–H bending
of different –CH 2
1660
spectra of (a) pure PVP (b) PVP-MnR3ROR4R
Crystalline phase was identified as MnR3ROR4R and the
crystallite size was obtained as 6±1 nm from X-ray line
profile fitting. As compared to the average particle size of
6.1±0.1 nm obtained from TEM analysis in Fig. 2, which
reveal nearly single crystalline nature of these
nanoparticles.
Relative Frequency
35
30
25
20
15
c)
1642
–C–N stretching
–C–N stretching
D=6,1 nm
=0,1
0,0
0 20 40 60 80
0 20 40 60 80
Temperature, (K)
Figure 3. Zero-field-cooled (ZFC) and field-cooled (FC)
magnetization curves PVP-MnR3ROR4R nanocomposite.
The sample has hystheresis with small coercivity and
remanenet magnetization at 40 K, resembling the
superparamagnetic state. a.c. conductivity measurements
on PVP-MnR3ROR4 Rnanocomposite revealed a conductivity in
-7 -1
the order of 10P
P S·cmP lower frequencies (Fig. 3). The
conductivity changes with respect to frequency can be
+2
explained by electronic exchange occuring between MnP
+3
’
and MnP in sublattice of spinel lattice. The P
’’
of PVP-MnR3ROR4 Ras a function of frequency are
found to be slightly temperature dependent.
* Corresponding author: hbaykal@fatih.edu.tr
[1] Z. Durmu., A. Baykal, H. Kavas, M. Direkçi, M.S. Toprak,
Polyhedron, 28, 2119-2122 (2009).
[2] T. Ozkaya, A. Baykal, H. Kavas, Y. Koseoglu, M.S. Toprak,
Physica B 403 (2008) 3760–3764.
[3] A. Baykal, Y. Koseoglu, M. Senel, Cent. Eur. J. Chem. 5(1)
2007 169–176.
[4] Z. Durmu, H. Kavas, A. Baykal, M.S. Toprak, Cent. Eur. J.
Chem. 7(3) 2009 555-559.
10
5
0
5,0 5,5 6,0 6,5 7,0 7,5
Diameter (nm)
Figure 2. TEM micrograph of PVP-MnR3ROR4R and calculated
histogram from several TEM images with a log-normal fitting.
6th Nanoscience and Nanotechnology Conference, zmir, 2010 717