Synthesis and Magnetic Properties of FePt /Silica Core-Shell Nanoparticles

Abstract:

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FePt nanoparticles (NPS), ~2nm in diameter, were synthesized and then coated with silica (SiO2) shells ~1.5nm-thick using reverse micelles as nanoreactors. The silica-coated FePt core–shell (FePt @silica) NPS were characterized by direct techniques of transmission electron microscopy (TEM). The results showed that the silica shells prevented the aggregation in liquid comparing to their bare counterparts. The as-synthesized FePt@SiO2 NPS exhibited essential characteristics of superparamagnetic behavior, as investigated by a vibrating sample magnetometer (VSM). X-ray diffraction (XRD) studies proved that the annealing at 700 °C for 30min under argon atmosphere caused the crystal structure of FePt core to transform from disordered face centered cubic (fcc) to the chemically ordered L10 FePt with face-centered tetragonal (fct) structure. This phase transition caused the change of magnetic properties of the FePt@SiO2 particles from superparamagnetism to ferromagnetism.

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Periodical:

Edited by:

Jinsheng Liang and Lijuan Wang

Pages:

291-295

DOI:

10.4028/www.scientific.net/AMR.178.291

Citation:

C. X. Li et al., "Synthesis and Magnetic Properties of FePt /Silica Core-Shell Nanoparticles", Advanced Materials Research, Vol. 178, pp. 291-295, 2011

Online since:

December 2010

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$35.00

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