Optimal field-free magnetization switching via spin-orbit torque on the surface of a topological insulator
Abstract
We present an optimal field-free protocol for current-induced switching of a perpendicularly magnetized ferromagnetic insulator nanoelement on the surface of a topological insulator. The time dependence of in-plane components of the surface current, which drives the magnetization reversal via the Dirac spin-orbit torque with minimal Joule heating, is derived analytically as a function of the switching time and material properties. Our analysis identifies that energy-efficient switching is achieved for vanishing damping-like torque. The optimal reversal time that balances switching speed and energy efficiency is determined. When we compare topological insulators to heavy-metal systems, we find similar switching costs for the optimal ratio between the spin-orbit torque coefficients. However, topological insulators offer the advantage of tunable material properties. Finally, we propose a robust and efficient simplified switching protocol using a down-chirped rotating current pulse, tailored to realistic ferromagnetic/topological insulator systems.
Keywords
Cite
@article{arxiv.2406.09287,
title = {Optimal field-free magnetization switching via spin-orbit torque on the surface of a topological insulator},
author = {Ivan P. Miranda and Grzegorz J. Kwiatkowski and Cecilia M. Holmqvist and Carlo M. Canali and Igor S. Lobanov and Valery M. Uzdin and Andrei Manolescu and Pavel F. Bessarab and Sigurður I. Erlingsson},
journal= {arXiv preprint arXiv:2406.09287},
year = {2024}
}