Investigating perpendicular magnetic anisotropy in magnetic thin films and multilayers with the magneto-optical Kerr effect

A deeper understanding of magnetic systems exhibiting perpendicular magnetic anisotropy (PMA), including magnetic multilayers, intermetallic compounds, and alloys, has attracted attention owing to their broad technological applications, particularly in magnetic data storage devices. Among available experimental approaches, magneto-optical techniques, particularly the magneto-optical Kerr effect (MOKE), have proven powerful and widely used for investigating magnetic materials. In this work, we proposed a high-resolution optical alignment protocol and an analytical-instrumental analyzer-angle-resolved magnetometry methodology, based on the Jones formalism, to extract Kerr rotation angles from measurements on PMA samples. The optimization of the polar MOKE (p-MOKE) response from fractional MOKE signals is discussed, and characterization of asymmetric hysteresis loops associated with different magnetic states along magnetization-reversal dynamics. The proposed methodology enables the determination of the Kerr rotation angle, fractional MOKE signal optimization, and analysis of magnetic-state-dependent hysteresis behavior. We obtained good agreement between the theoretical model and experimental measurements. Overall, the discussed methodology provides enhanced analytical capabilities and access to a broader range of parameters for the study of magnetic systems exhibiting PMA compared with which is typically exploited. As case studies, the presented approach is applied to two magnetic systems: [Co60Fe40/Pt]5 multilayer and MnGaGe thin film.