Thickness dependence of unidirectional spin-Hall magnetoresistance in metallic bilayers

Abstract

A nonlinear magnetoresistance - called unidirectional spin-Hall magnetoresistance - is recently experimentally discovered in metallic bilayers consisting of a heavy metal and a ferromagnetic metal. To study the fundamental mechanism of the USMR, both ferromagnetic and heavy metallic layer thickness dependence of the USMR are presented in a Pt/Co/AlOx trilayer at room temperature. To avoid ambiguities, second harmonic Hall measurements are used for separating spin-Hall and thermal contributions to the non-linear magnetoresistance. The experimental results are fitted by using a drift-diffusion theory, with parameters extracted from an analysis of longitudinal resistivity of the Co layer within the framework of the Fuchs-Sondheimer model. A good agreement with the theory is found, demonstrating that the USMR is governed by both the spin-Hall effect in the heavy metallic layer and the metallic diffusion process in the ferromagnetic layer.

References in corpus (4)

• Temperature dependence of spin diffusion length and spin Hall angle in Au and Pt
• Large Unidirectional Magnetoresistance in a Magnetic Topological Insulator
• Theory of unidirectional spin Hall magnetoresistance in heavy-metal/ferromagnetic-metal bilayers
• Electrical detection of magnetization reversal without auxiliary magnets

Cited by in corpus (7)

• Effects of transition-metal spacers on the spin-orbit torques, spin Hall magnetoresistance, and magnetic anisotropy of Pt/Co bilayers
• Unidirectional orbital magnetoresistance in light metal/ferromagnet bilayers
• Unidirectional Magnetoresistance in Antiferromagnet/Heavy-metal bilayers
• Large Unidirectional Magnetoresistance in Metallic Heterostructures in the Spin Transfer Torque Regime
• Theory of unidirectional magnetoresistance and nonlinear Hall effect
• Unidirectional spin Hall magnetoresistance and spin-orbit torques in HM${}_1$/Co/HM${}_2$ trilayer systems
• Fluctuation theorem for spin transport at insulating ferromagnetic junctions