Extraordinary efficient spin-orbit torque switching in (W, Ta)/epitaxial-Co60Fe40/TiN heterostructures

TL;DR

This paper demonstrates highly efficient spin-orbit torque switching in epitaxial heterostructures with giant spin Hall angles and low switching currents, advancing energy-efficient spintronic devices.

Contribution

It reports unprecedented spin Hall angles and low switching currents in epitaxial (W, Ta)/CoFe/TiN heterostructures, highlighting the importance of epitaxial interfaces for spintronics.

Findings

Giant spin Hall angle of 28.67 in W-based structures.

Ultra-low switching current density of 1.82 MA/cm2 in W/CoFe/TiN.

High interfacial spin mixing conductance and low spin memory loss.

Abstract

The giant spin Hall effect in magnetic heterostructures along with low spin memory loss and high interfacial spin mixing conductance are prerequisites to realize energy efficient spin torque based logic devices. We report giant spin Hall angle (SHA) of 28.67 (5.09) for W (Ta) interfaced epi- Co60Fe40/TiN structures. The spin-orbit torque switching current density (J_Crit) is as low as 1.82 (8.21) MA/cm2 in W (Ta)/Co60Fe40(t_CoFe)/TiN structures whose origin lies in the epitaxial interfaces. These structures also exhibit very low spin memory loss and high spin mixing conductance. These extraordinary values of SHA and therefore ultra-low J_Crit in semiconducting industry compatible epitaxial materials combinations open up a new direction for the realization of energy efficient spin logic devices by utilizing epitaxial interfaces.