Field-free spin-orbit switching of canted magnetization in Pt/Co/Ru/RuO2(101) multilayers

TL;DR

This paper demonstrates field-free current-induced switching of perpendicular magnetization in Pt/Co/Ru/RuO2(101) multilayers by leveraging a tilted easy axis and current injection along the RuO2[010] axis, advancing spin-orbit-torque memory technology.

Contribution

It introduces a novel method for achieving field-free switching by exploiting a tilted easy axis in multilayers with RuO2, optimizing the tilt to reduce switching current.

Findings

Successful demonstration of field-free switching in the system.

Current injection along RuO2[010] induces out-of-plane effective field.

Optimizing Ru layer thickness reduces critical switching current.

Abstract

Enabling field-free current-induced switching of perpendicular magnetization is essential for advancing spin-orbit-torque magnetic random access memory technology. Our research on the Pt/Co/Ru/RuO2(101) system has successfully demonstrated field-free switching through current injection along the RuO2[010] axis. We discovered that the system exhibits a tilted easy axis, inclined from the out-of-plane towards the RuO2[-101] direction. The application of current perpendicular to this tilted axis generates a substantial out-of-plane effective field, which facilitates field-free magnetization switching. Our results also indicate that adjusting the thickness of the Ru layer to optimize the tilt angle can significantly reduce the critical switching current density. This work provides a viable strategy for controlling the tilting magnetization, essential for the development of RuO2-based magnetic devices.