Microstructural origin of the anomalous shearing of perpendicular M-H loops of CoCr-based media

Anomalous shearing of perpendicular M-H loops occurs for both particulate and continuous CoCr-based perpendicular media. It is suggested from this study that, depending on the film microstructure, there are two different origins on such a phenomenon. For films with large intercolumnar separation, the contribution of the column shape anisotropy to the total demagnetizing factor is responsible for the deshearing of the loops. For continuous perpendicular films, the intergranular exchange coupHng controls the magnetization reversal process and the wall-motion-like reversal explains the anomalous shearing of the loops. The square and unsheared perpendicular M-H loops of very thin CoCr films deposited on difilerent underlayers originate from their excellent perpendicular orientation and large intercolumnar nonmagnetic separation due to the columnar growth nature of the sputter-deposited films.