Controlling the Spin Torque Efficiency with Ferroelectric Barriers

TL;DR

This paper presents a theoretical study showing that ferroelectric barriers in magnetic tunnel junctions can be used to electrically control spin transfer torque efficiency and tunneling magneto- and electroresistance, enabling new ways to manipulate magnetic states.

Contribution

It introduces a theoretical framework for controlling spin torque efficiency via ferroelectric polarization switching in magnetic tunnel junctions.

Findings

Spin transfer torque efficiency can be tuned by ferroelectric polarization.

Bias dependence of tunneling magneto- and electroresistance is controllable.

Switching ferroelectric polarization affects magnetic noise and dynamic states.

Abstract

Non-equilibrium spin-dependent transport in magnetic tunnel junctions comprising a ferroelectric barrier is theoretically investigated. The exact solutions of the free electron Schr\"odinger equation for electron tunneling in the presence of interfacial screening are obtained by combining Bessel and Airy functions. We demonstrate that the spin transfer torque efficiency, and more generally the bias-dependence of tunneling magneto- and electroresistance, can be controlled by switching the ferroelectric polarization of the barrier. This effect provides a supplementary way to electrically control the current-driven dynamic states of the magnetization and related magnetic noise in spin transfer devices.