Improvement of anomalous Hall effect of ferromagnetic thin films with perpendicular magnetization and its application to integrated non-volatile memory

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In this research, a ferromagnetic Hall effect of very thin film with perpendicular magnetic anisotropy were observed aiming for their application to non-volatic memory cells. An anomalous Hall effect (AHE) and a planar Hall effect (PHE) represent a perpendicular component and an in-plane component of the magnetization in the double-layered media. Since AHE and PHE have different symmetries regarding to the applied magnetic field H, it is easy to distinguish the AHE component, which is proportional to M, and PHE component, which is proportional to M^2, from the measured Hall voltage V_H. The Hall voltage of the double-layered film composed of Co-Cr-Ta and Ni-Fe layers was observed when the magnetic field is applied at a certain angle from the normal to the film plane. The observed V_H-H characteristics are regarded as a sum of Hall voltage outputs of PHE and AHE. The perpendicular and the in-plane components, which are regarded as the magnetization process of Co-Cr-Ta and that of Ni-Fe layer, respectively, can be easily determined from these characteristics. The Hall measurement is useful to study the magnetization characteristics in the double-layered media in perpendicular magnetic recording system. Furthermore, A new method for evaluating magnetic interaction among the particles in perpendicular magnetic recording layers under canted magnetic field have been proposed using Anomalous Hall measurement and VSM measurement. These results were very convenient to design Hall memory cells proposed in this project.