Reduction of energy cost of magnetization switching in a biaxial nanoparticle by use of internal dynamics

TL;DR

This paper presents a numerical and analytical approach to minimize energy consumption during magnetization switching in biaxial nanoparticles, balancing speed and stability for magnetic memory applications.

Contribution

It introduces optimal control paths and analytical estimates that reduce energy costs by leveraging internal dynamics and anisotropy effects.

Findings

Hard-axis anisotropy lowers energy cost due to internal torque.

Optimal switching time balances speed and energy efficiency.

Energy barrier and switching energy can be independently controlled.

Abstract

A solution to energy-efficient magnetization switching in a nanoparticle with biaxial anisotropy is presented. Optimal control paths minimizing the energy cost of magnetization reversal are calculated numerically as functions of the switching time and materials properties, and used to derive energy-efficient switching pulses of external magnetic field. Hard-axis anisotropy reduces the minimum energy cost of magnetization switching due to the internal torque in the desired switching direction. Analytical estimates quantifying this effect are obtained based on the perturbation theory. The optimal switching time providing a tradeoff between fast switching and energy efficiency is obtained. The energy cost of switching and the energy barrier between the stable states can be controlled independently in a biaxial nanomagnet. This provides a solution to the dilemma between energy-efficient writability and good thermal stability of magnetic memory elements.