The study of perpendicular magnetic anisotropy in the magnetic sensors with linear sensitivity using polarized neutron reflectometry

Abstract

The CoFeB sandwiched by Ta and MgO layers enables a perpendicular magnetic anisotropy (PMA) and provides a pathway for such application. In this paper, we reported the origin of PMA in CoFeB using the anomalous Hall effect (AHE) and polarized neutron reflectometry (PNR). From PNR experiments, we obtained the details of the magnetic and structural depth profiles inside the film. It is found that the PMA properties of CoFeB layers deposited above and under MgO layer are different and PNR measurements confirmed that a large PMA in the CoFeB above MgO layer is related to its low magnetization. Based on this PMA mechanism, we obtain a high sensitivity of AHE in the perpendicular CoFeB, which opens a new avenue to detect ultralow magnetic field.