Voltage-control of damping constant in magnetic-insulator/topological-insulator bilayers

TL;DR

This paper theoretically demonstrates that applying a voltage can significantly control the magnetic damping constant in ferromagnetic-insulator/topological-insulator bilayers, impacting spintronics device efficiency.

Contribution

It introduces a theoretical model for voltage-controlled magnetic damping in FI/TI bilayers, showing a potential tenfold tuning of damping with realistic parameters.

Findings

Damping can be tuned by an order of magnitude with 0.25V

Effective dissipation torque depends on applied voltage

Perspectives on voltage-induced magnon spin transport modulation

Abstract

The magnetic damping constant is a critical parameter for magnetization dynamics and the efficiency of memory devices and magnon transport. Therefore, its manipulation by electric fields is crucial in spintronics. Here, we theoretically demonstrate the voltage-control of magnetic damping in ferro- and ferrimagnetic-insulator (FI)/topological-insulator (TI) bilayers. Assuming a capacitor-like setup, we formulate an effective dissipation torque induced by spin-charge pumping at the FI/TI interface as a function of an applied voltage. By using realistic material parameters, we find that the effective damping for a FI with 10nm thickness can be tuned by one order of magnitude under the voltage with 0.25V. Also, we provide perspectives on the voltage-induced modulation of the magnon spin transport on proximity-coupled FIs.