Spin Hall Magnetoresistance and Spin–Orbit Torque Efficiency in Pt/FeCoB Bilayers

Abstract

The spin Hall magnetoresistance (SMR) of Pt/FeCoB bilayers with in-plane magnetocrystalline anisotropy was analysed with respect to a second order effect in the sensing current which acts, through the spin Hall effect in Pt, as a torque on the magnetization of the ferromagnetic layer and changes slightly its configuration. This leads to a small current dependent shift of the SMR curves in field that allows, in structures with a multidomain state (e.g. Hall bars), the determination of the sign of the magnetic remanence. The SMR measurements were performed as a function of the Pt thickness and the spin Hall angle, the diffusion length and the field-like and damping like SOT efficiency were determined. The results were compared with the values obtained from harmonic Hall voltage and SOT-ferromagnetic resonance (FMR) measurements and show a good agreement.

Manipulating the magnetic and transport properties by CuIr thickness in CoFeB/CuIr/IrMn multilayers

“…In FM/AF multilayer structures where EB or magnetoresistive properties are desired to be investigated, nonmagnetic metals such as Au, Pt, Ta, and W are the most used materials as a spacer layer due to their contribution to multilayer with their high spin-orbit coupling [1,9,25]. The structures in which these spacers are frequently seen particularly in studies investigating spintronic applications [4][5][6][7]26]. On the other hand, owing to its suitable interlayer exchange coupling and its larger spin Hall angle, CuIr is a promising material proposed as a spacer layer or as an underlayer in the multilayers [27,28].…”

Spin Currents at the Interface and Spin Hall Torque

“…By projecting all the vectors onto the plane perpendicular to the magnetization, one finds the DL in the direction of the injected magnetic moment and the FL in the perpendicular direction. The harmonic Hall method permits a detailed characterization of the two components and reveals that the FL is often much smaller than the DL and that they both depends on the thicknesses of the two layers [13], [14] .…”