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 a magnetic field perpendicular to the current direction, whereas AC excitation enables a linear response with near-zero offset to a magnetic field aligned with the current direction, driven by the spin–orbit torque effect. Moreover, the AC excitation effectively mitigates low-frequency 1/f noise down to sub-μV/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.