Transmission electron microscopic analysis of microstructural features in magnetic recording media

A study of the relationships between the microstructure and magnetic properties of cobalt alloy magnetic thin films and chromium underlayers deposited onto circumferentially textured NiP/Al substrates is presented. The variation of the chromium microstructure as a function of argon pressure and substrate temperature during sputtering is analyzed using high-resolution scanning electron microscopy and transmission electron microscopy (TEM). This combination shows that the layers grow in columns which have increasing physical separation with increasing pressure and decreasing temperature. Crystallographic grain separation, however, follows a different trend because intercolumnar crystallographic alignment decreases with increasing temperature. TEM is also used to show how the growth of the chromium underlayer affects the cobalt alloy layer and to analyze the resulting microstructures in different magnetic alloy layers