Effect of Ta and Cu spacer layers on the spin Hall angle in NiFe/Ta/IrMn and NiFe/Cu/IrMn structures

The influence of Ta and Cu spacers in NiFe/Ta/IrMn and NiFe/Cu/IrMn structures on the angular dependences of the planar Hall effect (PHE) and the spin current caused by the spin-orbit torque (SOT) was revealed. The studies were carried out in the ranges of electric current and external magnetic field, in which the current and field values do not affect the $R_\mathrm{PHE}$ ($\varphi_\mathrm{EX}$) dependences, leaving the exchange bias unchanged. Adding a spacer layer under these conditions reduces the resistance of the planar Hall effect $R_\mathrm{PHE}$ and affects the spin current generated in the IrMn/Spacer layers. This is expressed in a decrease in the spin Hall angle for NiFe/Ta/IrMn and NiFe/Cu/IrMn with an increase in the thickness of the spacer layer.