Efficient Switching of 3-Terminal Magnetic Tunnel Junctions by the Giant Spin Hall Effect of $\rm{Pt}_{85}\rm{Hf}_{15}$ Alloy

TL;DR

This paper demonstrates that using a $ m{Pt}_{85} m{Hf}_{15}$ alloy enhances the efficiency of spin Hall torque in 3-terminal magnetic tunnel junctions, significantly reducing switching currents and advancing magnetic memory technology.

Contribution

It introduces the use of a $ m{Pt}_{85} m{Hf}_{15}$ alloy to improve spin Hall torque efficiency in magnetic tunnel junctions, showing a twofold reduction in switching current densities.

Findings

$ m{Pt}_{85} m{Hf}_{15}$ reduces switching current densities by ~2x compared to pure Pt.

The alloy enables efficient switching with nanosecond-scale current pulses.

The approach supports development of energy-efficient magnetic memory devices.

Abstract

Recent research has indicated that introducing impurities that increase the resistivity of Pt can enhance the efficiency of the spin Hall torque it generates. Here we directly demonstrate the usefulness of this strategy by fabricating prototype 3-terminal in-plane-magnetized magnetic tunnel junctions that utilize the spin Hall torque from a $\rm{Pt}_{85}\rm{Hf}_{15}$ alloy, and measuring the critical currents for switching. We find that $\rm{Pt}_{85}\rm{Hf}_{15}$ reduces the switching current densities compared to pure Pt by approximately a factor of 2 for both quasi-static ramped current biases and nanosecond-scale current pulses, thereby proving the feasibility of this approach to assist in the development of efficient embedded magnetic memory technologies.