Magnetization dynamics driven by displacement currents across a magnetic tunnel junction

C. K. Safeer, Paul S. Keatley, Witold Skowroński, Jakub Mojsiejuk, Kay Yakushiji, Akio Fukushima, Shinji Yuasa, Daniel Bedau, Fèlix Casanova, Luis E. Hueso, Robert J. Hicken, Daniele Pinna, Gerrit van der Laan, Thorsten Hesjedal

Published 2024-05-09Version 1

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.