Spin Hall magnetoresistance sensor using AuxPt1-x as the spin-orbit torque biasing layer

Abstract

We report on investigation of a spin Hall magnetoresistance sensor based on NiFe/AuxPt1-x bilayers. Compared to NiFe/Pt, the NiFe/AuxPt1-x sensor exhibits a much lower power consumption (reduced by about 57%) due to 80% enhancement of spin-orbit torque efficiency of AuxPt1-x at an optimum composition of x = 0.19 as compared to pure Pt. The enhanced spin-orbit torque efficiency allows us to increase the thickness of NiFe from 1.8 nm to 2.5 nm without significantly increasing the power consumption. We show that, by increasing the NiFe thickness, we were able to improve the working field range (±0.86 Oe), operation temperature range (150 °C), and detectivity (0.71 nT/ Hz at 1 Hz) of the sensor, which is important for practical applications.