Magnetization dynamics driven by displacement currents across a magnetic tunnel junction

TL;DR

This paper investigates how displacement currents at gigahertz frequencies influence magnetization dynamics in magnetic tunnel junctions, revealing large currents induce magnetic effects without damaging the barrier, advancing high-speed spintronic device development.

Contribution

It demonstrates the impact of capacitive displacement currents on magnetization dynamics in MTJs at high frequencies, a novel insight for spintronics applications.

Findings

Large displacement currents induce magnetization dynamics.

Displacement currents generate Oersted fields and spin-orbit torques.

Capacitive impedance significantly affects high-frequency magnetotransport.

Abstract

Understanding the high-frequency transport characteristics of magnetic tunnel junctions (MTJs) is crucial for the development of fast-operating spintronics memories and radio frequency devices. Here, we present the study of frequency-dependent capacitive current effect in CoFeB/MgO-based MTJs and its influence on magnetization dynamics using time-resolved magneto-optical Kerr effect technique. In our device operating at gigahertz frequencies, we find a large displacement current of the order of mA's, which does not break the tunnel barrier of the MTJ. Importantly, this current generates an Oersted field and spin-orbit torque, inducing magnetization dynamics. Our discovery holds promise for building robust MTJ devices operating under high current conditions, also highlighting the significance of capacitive impedance in high frequency magnetotransport techniques.