Extended magneto optic method to explore the longitude magneto optic Kerr effect of the magnetic ultrathin film grown on optically anisotropic substrate

The traditional magneto optic Kerr effect (MOKE) method is extended and the new method can be applied to investigate the magnetic properties of magnetic ultrathin film even multilayer containing anisotropic optical medium as long as we choose a proper coordinate system. Based on this method, any interface structure—magnetic ultrathin film grown on optically anisotropic substrate—can be explored by MOKE. The computer simulation shows relation between longitude Kerr rotation and incident angle. A further analysis indicates that the three elements of dielectric tensor of the anisotropic substrate play different roles in determining the relation between Kerr rotation and incident angle. Besides, the influence of the three dielectric constants of the substrate on the Kerr rotation is also found and parameters of special crystals have been taken into simulation to find the error ratio that the traditional method results for multilayer containing anisotropic optical substrate. These results show that the extended method can enhance the accuracy of measurement and help us to choose proper substrate for the ultrathin magnetic films when using MOKE to explore them.

► We extended traditional matrix MOKE method for anisotropic optical medium.
► We explored special interface structures based on new method.
► We got relation between longitude Kerr rotation and anisotropic substrates.
► Extended method is more exact than traditional one.