Spin-orbit-torque-enabled three-dimensional magnetic field sensor with low offset and high sensitivity

Abstract

In this work we demonstrate a spin-orbit-torque (SOT) magnetic field sensor, designed as a Ta/Co⁢Fe⁢B/Mg⁢O structure, with high sensitivity and capable of active offset compensation in all three spatial directions. This is described and verified in experiment and simulation. The measurements of magnetic fields showed an offset of 35, 42, and 3 μ⁢T for 𝑥-, 𝑦-, and 𝑧-fields respectively. Furthermore, the sensitivities of these measurements had values of 590, 580, and 490 VA⁻¹ T⁻¹ in the 𝑥-, 𝑦-, and 𝑧-direction, respectively. In addition, the robustness to bias fields is demonstrated via experiments and single-spin simulations by applying bias fields in the 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 ±1 mT. The extraction of the SOT parameters 𝜂DL and 𝜂FL is shown via an optimization of a single-spin curve to the experimental measurements.