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Proceedings of the 4th International Conference on

Nanostructures (ICNS4)12-14 March 2012, Kish Island, I.R. Iran

Abstract Book|INST| Sharif University of Technology| 149

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Y-Pt- Fe3O4 nanoparticles were prepared by a simple method. Syn-thesis of nanoparticles of Fe3O4 was rst performed. Then Pt- Fe3O4nanoparticles were prepared with adding K2PtCl6 in Fe3O4 nanopar-

ticles solvent via reduction of K2PtCl6 in Fe3O4 nanoparticles by

NaBH4. For studying the effect of rare earth oxides on Pt- Fe3O4nanoparticles, Y2O3 was added to the Pt- Fe3O4 solvent. The synthe-

sized nanoparticles were characterized by X-ray diffraction (XRD)

and scanning electron microscopy (SEM). These nanoparticles have

chemically disordered structures. Susceptibility of prepared nanopar-

ticles was measured by Susceptometer. The hysteresis loop of Y-Pt-

Fe3O4 nanoparticles was taken by vibrating sample magnetometer

(VSM). The asmade nanoparticles have coercivity below 100 Oe and

are superparamagnetic in room temperature.

Keywords: Y-Pt-Fe3o4 nanoparticles; Magnetic properties; Superpara-

magnetic; Coersivity; Susceptibility

Z. Golsanamloua*, M. M Golzana, A. Hassanzadehba Department of Physics, University of Urmia, 165, Iranb

Department of Chemistry, University of Urmia, 165, Iran*[email protected]

Synthesis of Superparamagnec Nanoparcles with

Adding Yrium Oxide on Pt-Fe3O4 Nanoparcles

Nanocrytalline samples of La0.7Sr0.3MnO3 were synthesized by me-chanical activation method in ambient conditions and post sintering

at 900 C. The structural, magnetotransport, and magnetovolume

properties of the samples were investigated. The results show a metal-

insulator transition at TMI = 165 K, a ferro-paramagnetic transition at

TC = 160 K and a colossal magnetoresistance (CMR) value of about

40% under the eld of 1.5 T around TMI, which are markedly affected

by the small grain size (9 nm) of the studied samples. This is attributed

to the enhanced intergrain resistivity and spin-polarized tunnelling be-

tween neighbouring grains in the present granular samples. Besides,

the anomalous behaviour of magnetoresistance, thermal expansion

and its coefcient observed around TC of the samples can be explained

on the basis of a magnetic two-phase state.

Keywords: Manganites; Magnetoresistance; Thermal expansion; Me-

chanical activation

Sh. Tabatabai Yazdi*, Sh. Abareshi, N. Tajabor, M. Rezaee Roknabadi, M.BehdaniDepartment of Physics, Faculty of Sciences, Ferdowsi University, Mashhad91775-1436, Iran*[email protected]

Magnetotransport and Magnetovolume Eects in

La0.7Sr0.3MnO3 Nanocrystalline Perovskites Prepared by

Mechanical Acvaon Method

In this work, magnetic nanoparticles were generated by pulsed laser ir-

radiation on the Nd-Fe-B-C magnetic target in Distilled water. Charac-

terization of nanoparticles in terms of size, shape, chemical composition

and magnetic properties was carried out by transmission electron mi-

croscopy (TEM), energy dispersive X-ray (EDAX), Fourier transform

infrared spectroscopy (FTIR), magnetic force microscope (MFM). The

exposure times were performed on 1, 5 and 10 min. increasing of the

exposure time leads to reduce the mean diameter of the nanoparticles,

with minimum size of around 3 nm, growth of the nanoparticle number

and decreasing of the nanoparticle creation rate. The chemical compo-

sition of nanoparticles was similar to the bulk sample. MFM shows thatthe nanoparticles have the magnetic properties.

Keywords:Magnetic nanoparticles; Nd:YAG Laser; Nd-Fe-B-C magnet

S. Seifollahi, H. Dehghanpour*Department of physics, Tafresh University, Tafresh, 39518-79611, Iran*[email protected]

Physical Properes of Magnec Nd-Fe-B-C Nanoparcles

Generated in Dislled Water Using Nd:YAG Laser

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The inuence of Co concentration (x) on the structural, magneto-opti-

cal properties of CoxTi1-xO2 lms has been investigated. The lms were

deposited by spray pyrolysis technique on Si(100) substrates at 475C

using a hydro-alcoholic solution containing of titanium (iv) isopropox-

ide and Co(NO3)2 with various Co-doping levels of x=0, 0.003, 0.008,

and 0.015. The effect of annealing atmosphere on structural and elec-

tronic structure of the lms was investigated. X-ray diffraction analysis

shows that the lms have pure phase of TiO2. Atomic force microscope

(AFM) study shows that the annealing does not change signicantly

the grain size and microstructure of the samples. Room temperature

magneto-optical characterization in polar mode shows hysteresis loops

for the samples annealed in H2 gas as well as a paramagnetic behav-

iour for the samples which were annealed in air. X-ray photoelectron

spectroscopy (XPS) analysis shows the presence of Co2+ high spin forsample with x=0.008 which annealed in H2. It shows that Co atoms are

bounded to oxygen and there is no metallic bound in anatase structure.

Therefore, the origin of magnetization could be attributed to the role of

oxygen vacancies in anatase thin lms.

Keywords: Diluted magnetic semiconductors; Grazing incident angle

of X-Ray diffraction; Magneto-optical Kerr effect

M. Karimipoura, b, c*, M. Magetod, e, N. Shahtahmasebia, b, M. Rezaee Roknaba-da, b, R. Etefagha, b, E. Azhira, b, M. Mwamburie, Z. Topaliand, P. Svedlindhda Nano Research Centre, Faculty of Basic Science, Ferdowsi University ofMashhad, Mashhad, Iranb Department of Physics, Faculty of Basic Science, Ferdowsi University ofMashhad, Mashhad, Iranc Department of Physics and Astronomy, Uppsala University, Uppsala 516,SE-75120, Sweden

Room Temperature Magnezaon of Co-doped TiO2

Thin Films Prepared by Spray Pyrolysis Technique

dDepartment of Engineering Sciences, ngstrom Laboratory, Uppsala Uni-versity, Uppsala 534, SE-751 21, Swedene Department of Physics, Moi University, Eldoret 1125, Kenya*[email protected]

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