Transactions of Nonferrous Metals Society of China
JOURNAL OF RAILWAY SCIENCE AND ENGINEERING
|Vol. 17 No. 6 December 2007|
（1. School of Engineering, University of Tokyo, Bunkyo-ku, Tokyo 113-8656, Japan; 2. Laboratory of Crystallography, Department of Materials, ETH-Zürich, CH-8093 Zürich, Switzerland; 3. School of Materials Science and Engineering, Central South University, Changsha 410083, China ）
Abstract:A simplified model was developed to describe the Curie temperature suppression of ferromagnetic nanoparticles. Based on a size and shape dependent model of cohesive energy, the critical temperature variations of ferromagnetic nanoparticles were deduced. It is predicted that the Curie temperature of nanoparticles depends on both size and shape conditions, among which the temperature suppression is strongly influenced by the particle size and the shape effect is comparably minor. The calculation values for freestanding nanoparticles are in good agreement with other theoretical model and the experimental results. The model is also potential for predictions for the nanoparticles embedded in different substrates.
Key words: nanoparticle; size effect; shape effect; ferromagnet; Curie temperature