The Stoner-Wohlfarth model of Ferromagnetism: Dynamic and Statistical properties

Abstract

The physics of magnetic state change or reversal in single domain magnetic grains (called Stoner particles) is interesting from the fundamental as well as the applied points of view. A change in magnetization can be finely tuned with a specific time variation o f an externally applied magnetic field. It may also occur naturally (without application of a field) at very low tempe rature with quantum tunneling and at higher temperature with thermal excitation. The optimal (usually shortest) time altering the magn etisation along with the smallest applied magnetic field are sought in technological applications s uch as high-density reading or writing of information, spintronics, quantum inform ation and quantum communication systems. This work reviews the magnetization change with a time dependent field and tem perature and discusses the time it takes to alter the magnetization as a function of the control parameter chosen, temperature and material parameters.