Biased quasi ballistic spin torque magnetization reversal

TL;DR

This paper investigates the fundamental speed limits of ultra-fast magnetization reversal using spin torque, demonstrating coherent control techniques to achieve quasi-ballistic switching in magnetic memory cells.

Contribution

It introduces a method to suppress magnetization ringing and achieve near ballistic reversal by adapting pulse duration to precession periods.

Findings

Suppression of magnetization ringing enables faster switching

Coherent control allows quasi-ballistic reversal in a single precessional turn

Achieves ultra-fast magnetization reversal with minimal residual oscillations

Abstract

We explore the fundamental time limit of ultra fast spin torque induced magnetization reversal of a magnetic memory cell. Spin torque precession during a spin torque current pulse and free precessional magnetization ringing after spin torque pulse excitation is detected by time resolved magneto transport. Adapting the duration of the spin torque excitation pulse to the spin torque precession period allows suppression of the magnetization ringing and thus coherent control of the final orientation of the magnetization. In the presence of a hard axis bias field such coherent control enables an optimum ultra fast, quasi ballistic spin torque magnetization reversal by a single precessional turn directly from the initial to the reversed equilibrium state.