Ratchet Effect in Magnetization Reversal of Stoner Particles

TL;DR

This paper introduces a novel method for magnetization reversal in Stoner particles that significantly lowers the required switching field by using a time-dependent magnetic field aligned with the magnetization's motion, leveraging energy supply to overcome barriers.

Contribution

It proposes a new strategy utilizing a dynamic magnetic field to reduce the minimal switching field, contrasting with traditional static field methods.

Findings

Switching field proportional to damping constant in weak damping regime

Energy supplied from time-dependent field enables barrier crossing

Method reduces required magnetic field strength for reversal

Abstract

A new strategy is proposed aimed at substantially reducing the minimal magnetization switching field for a Stoner particle. Unlike the normal method of applying a static magnetic field which must be larger than the magnetic anisotropy, a much weaker field, proportional to the damping constant in the weak damping regime, can be used to switch the magnetization from one state to another if the field is along the motion of the magnetization. The concept is to constantly supply energy to the particle from the time-dependent magnetic field to allow the particle to climb over the potential barrier between the initial and the target states.