SOT Enabled 3D Magnetic Field Sensor with Low Offset and High Sensitivity

TL;DR

This paper presents a novel SOT-based 3D magnetic field sensor with high sensitivity and active offset compensation, verified through experiments and simulations, advancing magnetic sensing technology.

Contribution

The work introduces a Ta/CoFeB/MgO structure sensor capable of active 3D offset compensation and high sensitivity, with detailed experimental and simulation validation.

Findings

Offset of 36-50 μT in measurements

Sensitivities of 490-590 V A^{-1} T^{-1}

Robustness to bias fields demonstrated

Abstract

In this work we demonstrate a spin-orbit torque (SOT) magnetic field sensor, designed as a Ta/CoFeB/MgO structure, with high sensitivity and capable of active offset compensation in all three spatial directions. This is described and verified in both experiment and simulation. The measurements of magnetic fields showed an offset of 36, 50, and 37$\mathrm{\mu T}$ for x-, y-, and z-fields. Furthermore, the sensitivities of these measurements had values of 590, 580, and 490$\mathrm{V\,A^{-1}\,T^{-1}}$ in the x-, y-, and z-direction. In addition, the robustness to bias fields is demonstrated via experiments and single spin simulations by applying bias fields in y-direction. Cross sensitivities were further analyzed via single spin simulations performing a parameter sweep of different bias fields in the y- and z-direction up to $\pm$1mT. Finally, the extraction of the SOT parameters $\eta_\mathrm{DL}$ and $\eta_\mathrm{FL}$ is shown via optimization of a single-spin curve to the experimental measurements.