Calculation of the size dependence of the coercive force in fine particles

Author

Lyberatos, A. ; Chantrell, R.W.

Author_Institution

Lancashire Polytech., Preston, UK

Volume

26

Issue

5

fYear

1990

fDate

9/1/1990 12:00:00 AM

Firstpage

2119

Lastpage

2121

Abstract

A numerical micromagnetic model is employed to calculate the energy barrier for the reversal in a γFe₂O₃ particle of cubic shape. The model simulates magnetization reversal by coherent rotation and curling. It simulates the thermal fluctuations of the magnetization by a method or parametric optimization and gives the dependence of the coercive force on particle size. The size dependence of the switching field is a good qualitative fit to experimental data. A small reduction in the superparamagnetic size of γFe₂O ₃ particles is attributed to the surface imperfection. The flower magnetization configuration appears to be metastable over an intermediate size region, and a spontaneous transition to a vortex state of lower energy is expected at normal temperatures

Keywords

coercive force; iron compounds; magnetic properties of fine particles; magnetisation reversal; particle size; γFe₂O₃ particle; Fe₂O₃; coercive force; coherent rotation; cubic shape; curling; energy barrier; fine particles; flower magnetization configuration; magnetization; numerical micromagnetic model; parametric optimization; particle size; particulate recording media; reversal; size dependence; superparamagnetic size; surface imperfection; thermal fluctuations; vortex state; Coercive force; Energy barrier; Fluctuations; Magnetization reversal; Micromagnetics; Numerical models; Optimization methods; Shape; Surface fitting; Thermal force;

fLanguage

English

Journal_Title

Magnetics, IEEE Transactions on

Publisher

ieee

ISSN

0018-9464

Type

jour

DOI

10.1109/20.104639

Filename

104639