Critical current under an optimal time-dependent polarization direction for Stoner particles in spin-transfer torque induced fast magnetization reversal

TL;DR

This paper demonstrates that a carefully designed time-dependent polarization direction of spin-polarized current can significantly lower the critical current needed for fast magnetization reversal in uniaxial Stoner particles, optimizing reversal speed.

Contribution

It introduces a method to design the optimal time-dependent polarization direction to minimize critical current and maximize reversal speed in spin-transfer torque systems.

Findings

Optimal polarization shape dramatically reduces critical current

Fastest reversal achieved with specific polarization timing

Design principles for polarization direction in magnetic switching

Abstract

Fast magnetization reversal of uniaxial Stoner particles by spin-transfer torque due to the spin-polarized electric current is investigated. It is found that a current with a properly designed time-dependent polarization direction can dramatically reduce the critical current density required to reverse a magnetization. Under the condition that the magnitude and the polarization degree of the current do not vary with time, the shape of the optimal time-dependent polarization direction is obtained such that the magnetization reversal is the fastest.