Abstract
Thickness dependence of cap layer and soft underlayer (SUL), two important layers in a perpendicular magnetic recording (PMR) medium, has been investigated using the Hall effects measurement method. Hall voltage was found to be increasing with increasing cap layer thickness, which is quite different from that of a single layer ferromagnetic thin film case, where the Hall voltage is inversely proportional to the film thickness. For a fixed cap layer thickness, Hall voltage was found to be increasing with decreasing SUL thickness. The method can be applied to monitor the cap layer thickness in the manufacturing of capped media. A bi-layer model based on the experimental data predicts that in a stacked structure of different magnetic thin films with different anomalous Hall coefficients there exists a region where Hall voltage increases with increasing thickness of a layer compared to another one.
