Methodology for investigating the magnetization Process of the storage Layer in double-Layered perpendicular magnetic recording media using the anomalous Hall effect

The Hall effect is a useful phenomenon for evaluating the magnetization processes of the storage and back layers in double-layered perpendicular magnetic recording media. Although the Hall voltage in double-layered films has two components (an anomalous Hall term arising from the perpendicular component of magnetization and a planar Hall term originating from the in-plane component of magnetization), it is possible to separate the two contributions by symmetry arguments. However, in the case where the saturation field of the recording layer (RL) is comparable to that of the soft underlayer (SUL), or when the SUL dominates the signal because of its inherently high magnetic moment, it is difficult to separate the anomalous Hall effect (AHE) contributions from the RL and SUL individually. Here we propose a methodology that overcomes this limitation and allows the extraction of the magnetization process of the RL. We assume that an average perpendicular magnetization contributes to the anomalous Hall voltage in the double-layered perpendicular media. We compare the magnetization process of the RL obtained by using this approach to that measured with a magnetooptical Kerr effect (MOKE) system. The proposed technique may be useful in those situations in which alternative tools such as the MOKE system are not suitable for measuring the magnetization process.