Sensitivity enhancement of an anomalous Hall effect magnetic sensor by means of second-order magnetic anisotropy

The sensing performance of anomalous Hall effect (AHE) magnetic sensors is investigated in terms of their sensitivity, the power spectrum of their voltage noise, and their detectivity. Special attention is paid to the effect of the second-order anisotropy constant, K2, on the sensing performance. It is found that the sensitivity is strongly enhanced by tuning the value of K2 close to the boundary between the in-plane magnetized state and the conically magnetized state. It is also found that the detectivity is almost independent of K2 as long as the film is in-plane magnetized. These results provide fundamental insights into the design of high-performance AHE sensors.