Zero-field spin-orbit-torque switching driven by magnetic spin Hall effect

TL;DR

This paper demonstrates zero-field spin-orbit-torque switching driven by the magnetic spin Hall effect in bilayer materials, enabling magnetic and exchange bias control without external magnetic fields, advancing spintronic technology.

Contribution

It introduces the use of magnetic spin Hall effect in bilayer systems for zero-field switching, leveraging non-collinear spin textures in antiferromagnets.

Findings

Achieved simultaneous switching of magnetization and exchange bias without external magnetic field.

Identified the role of non-collinear spin textures in enabling symmetry-breaking in spin-current.

Paved the way for exploring magnetic spin Hall effects in various spin textures.

Abstract

Spin Hall effect plays an essential role in generating spin current from the injected charge current, following the Dyakonov-Perel rule that the directions of charge flow, spin flow and spin polarization are mutually perpendicular to each other. Recently, its generalization from an antiferromagnet, so-called magnetic spin Hall effect, has been studied and verified by measuring anomalous spin accumulations. Here, we investigate the magnetic spin Hall effect in bilayer materials made of a heavy metal and an antiferromagnet. The spin current generated by the magnetic spin Hall effect accomplishes spin-orbit-torque switching for ferromagnetic magnetization and exchange bias concurrently without any external magnetic field. The switching mechanism crucially relies on the non-collinear spin texture in the antiferromagnet, capable of generating symmetry-breaking components in the spin-current tensor so that the external magnetic field is no longer necessary. The zero-field concurrent switching of magnetization and exchange bias is a significant technological breakthrough. Furthermore, our findings pave the way to explore the magnetic spin Hall effects in various spin textures through spin-orbit-torque switching.