Theoretical Investigation of Hysteresis and Thermoremanent Magnetization in Multidomain Particles

University Of California-Santa Barbara, Santa Barbara CA

Investigators

Abstract

Newell EAR-0087687 The magnetic behavior of multidomain particles is governed by nucleation and disappearance of domain walls and by domain wall pinning. These processes have been studied intensively but never combined in a single self-consistent model. The object of this proposal is to develop a numerical micromagnetic model that includes magnetoelastic interactions with stress fields due to defects. The model will be unconstrained so that domain walls can nucleate or disappear spontaneously and be pinned by the stress fields. Results will be compared with domain observations of stressed magnetite, pyrrhotite and hematite. For each particle that is modeled, a systematic approach will be used to map out all major and minor magnetization curves as a function of applied field and temperature. These curves will be used to simulate a wide variety of isothermal and temperature dependent experiments.