Dual-mode operation of ring-shaped spin Hall magnetoresistance sensor with biaxial sensing capability

We present a spin Hall magnetoresistance sensor based on a NiFe/Pt multiring bridge structure, which exhibits high sensitivity and good linearity in two perpendicular directions within the sensor plane. Under DC excitation, it responds linearly to magnetic field perpendicular to the current direction, whereas AC excitation enables a linear response with near-zero offset to magnetic field aligned with the current direction, driven by spin-orbit torque effect. Moreover, the AC excitation effectively mitigates low-frequency 1/f noise down to sub-microvolt per sqrt(Hz) at 1 Hz. Systematic investigations have been performed to optimize the NiFe thickness while keeping the Pt thickness at 2 nm. The biaxial sensing capability offers a promising approach for multidimensional magnetic field detection in advanced sensing applications.