Crystallographic and structural analyses of perpendicular magnetic Co-Pt-B-O alloy films

CoPtBO reactive sputtered film is a new type of perpendicular recording media material with high perpendicular anisotropy fields and large perpendicular coercivities. To understand the origin of the magnetic properties, several materials parameters were explored. These included the effects of the introduced oxygen on the crystal structure, as well as the orientations and the microstructure of the CoPtBO films. With increasing the oxygen partial pressure, the crystallographic structure of CoPtBO alloy films were changed from face-centered-cubic (111) texture into hexagonal-close-packed (hcp) (001) texture. Pole figure analysis is a useful method to identify the crystalline structure of the oriented films. The strong hcp (001) texture and separation of the magnetic grains are the origin of the high Hk and large Hc of the films.