Field-Free Switching of Perpendicular Magnetic Tunnel Junction via Voltage-Gated Spin Hall Effect for Low-Power Spintronic Memory

TL;DR

This paper demonstrates a low-power, high-density spintronic memory using voltage-gated spin Hall effect and magnetic tunnel junctions, achieving fast write speeds with minimal energy consumption.

Contribution

It introduces a novel IrMn/CoFeB/MgO structure exhibiting significant VCMA effect and combines SHE and VCMA for efficient, field-free magnetization switching in spintronic memory.

Findings

VCMA effect of 39 fJ/Vm in IrMn/CoFeB/MgO structure

10-fold reduction in SHE switching current with voltage application

Power consumption of 8.5 fJ/bit for high-speed memory operations

Abstract

Spin Hall effect (SHE) and voltage-controlled magnetic anisotropy (VCMA) are two promising methods for low-power electrical manipulation of magnetization. Recently, magnetic field-free switching of perpendicular magnetization through SHE has been reported with the aid of an exchange bias from an antiferromagnetic IrMn layer. In this letter, we experimentally demonstrate that the IrMn/CoFeB/MgO structure exhibits a VCMA effect of 39 fJ/Vm, which is comparable to that of the Ta/CoFeB/MgO structure. Magnetization dynamics under a combination of the SHE and VCMA are modeled and simulated. It is found that, by applying a voltage of 1.5 V, the critical SHE switching current can be decreased by 10 times owing to the VCMA effect, leading to low-power operations. Furthermore, a high-density spintronic memory structure can be built with multiple magnetic tunnel junctions (MTJs) located on a single IrMn strip. Through hybrid CMOS/MTJ simulations, we demonstrate that fast-speed write operations can be achieved with power consumption of only 8.5 fJ/bit. These findings reveal the possibility to realize high-density and low-power spintronic memory manipulated by voltage-gated SHE.