Synthesis and fabrication of a thin film containing silica-encapsulated face-centered tetragonal FePt nanoparticles

A thin film containing silica encapsulated face-centered tetragonal FePt nanoparticles was synthesized by using sequential nanochemistry preparation techniques. The silica coating offered the alloy particles a physical barrier against sintering by modifying their diffusion rates and surface energies...

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Bibliografski detalji
Glavni autori: Yu, C, Caiulo, N, Lo, C, Tam, K, Tsang, S
Format: Journal article
Jezik:English
Izdano: 2006
Opis
Sažetak:A thin film containing silica encapsulated face-centered tetragonal FePt nanoparticles was synthesized by using sequential nanochemistry preparation techniques. The silica coating offered the alloy particles a physical barrier against sintering by modifying their diffusion rates and surface energies during the high-temperature annealing required for the fct phase transition. It was found that each quasi-spherical silica particle embracing the FePt can undergo self-assembly into a closely packed, ordered 2D array structure with identical interparticle spacing on a thin supporting film. A strong chemical attachment of the silica nanosphere to the oxide film was evident through a surface dehydroxylation reaction. A Langmuir-Blodgett (LB) deposition technique to control the arrangement of the silica encapsulated FePt on a substrate was carried out, followed by a high-temperature heat treatment and the heat-treated, silica-encapsulated sample displays magnetic hysteresis.