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

Abstract:

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.

• Periodical: Advanced Materials Research (Volume 178)
• Pages: 291-295
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.178.291
• Online since: December 2010
• Authors: Cui Xia Li, Zhi Hong Li, Xue Yan Du, Hai Xia Guo
• Keywords: Core-Shell, FePt Nanoparticle, Magnetic Property, Microemulsion, Silica

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