Thermoremanent magnetization III. Theory of multidomain grains

Abstract

A theory of thermoremanent magnetization is obtained for a Ferromagnetic material composed of multidomain particles. Relationships are derived between the blocking temperature and coercive force and also between the intensity of thermoremanent magnetization and the strength of the external field. These relationships appear to account rather well for the experimental results reported in an earlier paper. The theory is compared with various other explanations of thermoremanence, especially Néel's theory for single domain particles. The two theories seem to account in a natural way both for the resemblances and the differences between thermoremanent magnetizations in single domain and multi-domain particles.