Voltage-Induced Ferromagnetic Resonance in Magnetic Tunnel Junctions

TL;DR

This paper demonstrates voltage-induced ferromagnetic resonance in magnetic tunnel junctions driven by combined voltage-controlled magnetic anisotropy and spin transfer torque, revealing their comparable roles in high-frequency magnetization dynamics and enhancing microwave detection sensitivity.

Contribution

It introduces the combined effect of VCMA and ST in driving ferromagnetic resonance in MTJs and shows their equal importance in high-frequency applications.

Findings

VCMA and ST torques have similar magnitudes in low-resistance MTJs

Both torques significantly influence high-frequency magnetization dynamics

VCMA enhances the sensitivity of MTJ-based microwave detectors

Abstract

We demonstrate excitation of ferromagnetic resonance in CoFeB/MgO/CoFeB magnetic tunnel junctions (MTJs) by the combined action of voltage-controlled magnetic anisotropy (VCMA) and spin transfer torque (ST). Our measurements reveal that GHz-frequency VCMA torque and ST in low-resistance MTJs have similar magnitudes, and thus that both torques are equally important for understanding high-frequency voltage-driven magnetization dynamics in MTJs. As an example, we show that VCMA can increase the sensitivity of an MTJ-based microwave signal detector to the sensitivity level of semiconductor Schottky diodes.