Coherent spin-transfer precession switching in orthogonal spin-torque devices

TL;DR

This paper demonstrates fast, deterministic spin-transfer switching in orthogonal spin-torque devices at cryogenic temperatures, highlighting coherent precession and decoherence effects through experiments and macrospin simulations.

Contribution

It provides the first experimental evidence of sub-100 ps switching and analyzes the limitations of macrospin models in capturing decoherence phenomena.

Findings

Achieved 100 ps switching with a 10^{-5} error rate at 4 K

Observed coherent precessional switching at longer pulse durations

Identified ensemble decoherence effects impacting switching reliability

Abstract

We present experimental results and macrospin simulations of the switching characteristics of orthogonal spin-transfer devices incorporating an out-of-plane magnetized polarizing layer and an in-plane magnetized spin valve device at cryogenic temperatures. At $T=4$ K we demonstrate: high speed deterministic switching at short pulse lengths - down to 100 ps - with sufficient measurement statistics to establish a switching error rate of $10^{-5}$; coherent precessional switching at longer times; and ensemble decoherence effects at even longer times. Finite temperature macrospin models capture the precessional switching well but fail to fully reproduce all the decoherence and switching error behavior.