Field-free spin-orbit torque switching of an antiferromagnet with perpendicular N\'eel vector

TL;DR

This paper proposes a novel AFM memory device that achieves field-free, ultrafast switching of perpendicular Ne9el vector using orthogonal currents, promising high-speed, deterministic magnetic memory applications.

Contribution

It introduces a trilayer AFM/Insulator/Heavy Metal structure enabling field-free switching via orthogonal currents, advancing AFM memory technology.

Findings

Achieves reversible AFM switching with two orthogonal currents.

Switching occurs within 40 picoseconds.

Requires a current density of 1.79 x 10^11 A/m^2.

Abstract

The field-free spin-orbit torque induced 180{\deg} reorientation of perpendicular magnetization is beneficial for the high performance magnetic memory. The antiferromagnetic material (AFM) can provide higher operation speed than the ferromagnetic counterpart. In this paper, we propose a trilayer AFM/Insulator/Heavy Metal structure as the AFM memory device. We show that the field-free switching of the AFM with perpendicular N\'eel vector can be achieved by using two orthogonal currents, which provide the uniform damping-like torque and stagger field-like torque, respectively. The reversible switching can be obtained by reversing either current. A current density of 1.79 10^11A/m^2 is sufficient to induce the switching. In addition, the two magnetic moments become noncollinear during the switching. This enables an ultrafast switching within 40 picoseconds. The device and switching mechanism proposed in this work offer a promising approach to deterministically switch the AFM with perpendicular N\'eel vector. It can also stimulate the development of ultrafast AFM-based MRAM.