Microstructure/magnetic property relationships in CoCrPt magnetic thin films

Microstructural investigations of CoCrPt/Cr and CoCrPt/CrV magnetic thin film media were conducted in order to explain improved media performance as a function of increased Cr concentration in the magnetic layer and a predeposition treatment of the NiP plated Al substrate. Using High Resolution Transmission Electron Microscopy (HRTEM) and Selected Area Diffraction Patterns (SADP) it was found that for both underlayer structures, no significant microstructural differences (such as grain size, stacking fault density, orientation, crystalline phase, and bi-crystals) exist between samples grown with 13% Cr and 22% Cr. This indicates that Cr segregation to grain boundaries is the most likely mechanism for improved S/N ratio and higher coercivity. The increased coercivity observed in the treated samples is consistent with an increased grain size in the magnetic layer due to larger Cr underlayer grains.