Anomalous spin Hall magnetoresistance in Pt/Co bilayers

Abstract

We have studied the spin Hall magnetoresistance (SMR), the magnetoresistance within the plane transverse to the current flow, of Pt/Co bilayers. We find that the SMR increases with increasing Co thickness: the effective spin Hall angle for bilayers with thick Co exceeds the reported values of Pt when a conventional drift-diffusion model is used. An extended model including spin transport within the Co layer cannot account for the large SMR. To identify its origin, contributions from other sources are studied. For most bilayers, the SMR increases with decreasing temperature and increasing magnetic field, indicating that magnon-related effects in the Co layer play little role. Without the Pt layer, we do not observe the large SMR found for the Pt/Co bilayers with thick Co. Implementing the effect of the so-called interface magnetoresistance and the textured induced anisotropic scattering cannot account for the Co thickness dependent SMR. Since the large SMR is present for W/Co but its magnitude reduces in W/CoFeB, we infer its origin is associated with a particular property of Co.

References in corpus (12)

• Spin Seebeck insulator
• Theory of spin Hall magnetoresistance
• Observation of the spin Nernst effect
• Spin Hall magnetoresistance in antiferromagnet/heavy-metal heterostructures
• Rashba-Edelstein Magnetoresistance in Metallic Heterostructure
• Magnetoresistance due to edge spin accumulation
• The Spin Nernst effect in Tungsten
• Direct measurement of interfacial Dzyaloshinskii-Moriya interaction in X/CoFeB/MgO heterostructures with a scanning-NV magnetometer
• Intrinsic magnetoresistance in metal films on ferromagnetic insulators
• The effect of inserted NiO layer on spin-Hall magnetoresistance in Pt/NiO/YIG heterostructures
• Observation of transverse spin Nernst magnetoresistance induced by thermal spin current in ferromagnet/non-magnet bilayers
• Spin Hall magnetoresistance in antiferromagnet/normal metal bilayers

Cited by in corpus (14)

• Dzyaloshinskii-Moriya interaction and spin-orbit torque at the Ir/Co interface
• Field-free spin-orbit torque switching in Co/Pt/Co multilayer with mixed magnetic anisotropies
• Determination of spin Hall angle in heavy metal/CoFeB-based heterostructures with interfacial spin-orbit fields
• Highly efficient spin orbit torque in Pt/Co/Ir multilayers with antiferromagnetic interlayer exchange coupling
• Interfacial contributions to spin-orbit torque and magnetoresistance in ferromagnet/heavy-metal bilayers
• Interlayer exchange coupling through Ir-doped Cu spin Hall material
• Current-induced magnetization switching of exchange-biased NiO heterostructures characterized by spin-orbit torque
• Unconventional anomalous Hall effect in 3d/5d multilayers mediated by the nonlocal spin-conductivity
• Spin-orbit torques and spin Hall magnetoresistance generated by twin-free and amorphous Bi0.9Sb0.1 topological insulator films
• Spin-current-related magnetoresistance in epitaxial Pt/Co bilayers in the presence of spin Hall effect and Rashba-Edelstein effect
• Spin-orbit torque induced magnetisation dynamics and switching in CoFeB/Ta/CoFeB system with mixed magnetic anisotropy
• Stacking-order effect on spin-orbit torque, spin-Hall magnetoresistance, and magnetic anisotropy in Ni${}_{81}$Fe${}_{19}$-IrO${}_2$ bilayers
• Absence of Spin Hall Magnetoresistance in Pt/(CoNi)n multilayers
• Polar and quadratic magneto-optical Kerr effects in nonmagnetic/ferromagnet bilayers for spin-orbit torque measurements