Variation of magnetic properties along the film thickness in perpendicular thin film media investigated by optical method

Local variation of magnetic properties along the film thickness for CoNiCrTa perpendicular thin film media is discussed based on the magneto-optical analysis. It is found that the thickness of the bottom layer, which has low coercivity, is roughly estimated to be about 10 nm. Furthermore, the hysteresis loop of the bottom layer can be calculated by using magneto-optical multilayer model.