Manipulating the Voltage Dependence of Tunneling Spin Torques

TL;DR

This paper explores how to manipulate the voltage dependence of spin transfer torques in magnetic tunnel junctions to improve the design and performance of spin-based memory and logic devices.

Contribution

It introduces methods to control the bias dependence of spin torque components by engineering junction asymmetries and spin accumulation profiles.

Findings

Structural asymmetries affect torque bias dependence

Controlling spin accumulation modifies torque behavior

Engineering junctions enhances device efficiency

Abstract

Voltage-driven spin transfer torques in magnetic tunnel junctions provide an outstanding tool to design advanced spin-based devices for memory and reprogrammable logic applications. The non-linear voltage dependence of the torque has a direct impact on current-driven magnetization dynamics and on devices performances. After a brief overview of the progress made to date in the theoretical description of the spin torque in tunnel junctions, I present different ways to alter and control the bias dependence of both components of the spin torque. Engineering the junction (barrier and electrodes) structural asymmetries or controlling the spin accumulation profile in the free layer offer promising tools to design efficient spin devices.