Effects of plasma etching on orientation ratio for longitudinal recording media

Studies on the effects of rf plasma etching treatment on textured NiP/Al substrate on the properties of CoCrTaPt/CrMo longitudinal recording media were carried out. The dependence of coercivity (H _c), coercivity orientation ratio (OR), and disk surface roughness (R _a) on etching parameters, i.e., etching time, pressure, and power, were presented. It was found that by optimizing the etching process parameters, an increase of H _c and OR and a decrease of R _a could be achieved. It was observed that good preferred orientation is necessary for obtaining high OR. The increase of OR could be attributed to the cleaning effect or surface modification by the rf plasma etching treatment on the textured substrate.