CoCrPtTa single layer perpendicular magnetic recording media with carbon underlayer

Sputter-deposited amorphous carbon was applied as an underlayer for a Co₇₃Cr₁₈Pt₆Ta₃ single layer perpendicular magnetic recording medium. It is shown that the amorphous carbon underlayer can control the Co [001] preferred orientation of the Co₇₃Cr₁₈Pt₆Ta₃ magnetic recording layer and that the microcrystalline structure, magnetic properties, and read-write characteristics of Co₇₃Cr₁₈Pt₆Ta₃ media are greatly dependent on the carbon underlayer thickness. By x-ray diffraction experiments and transmission electron microscopy observations, it was confirmed that the distribution of the c-axis orientation of Co grains becomes broader in the direction perpendicular to the film surface with increasing carbon underlayer thickness. Furthermore, the Co₇₃Cr₁₈Pt₆Ta₃ medium with a thick carbon underlayer indicated a relatively high perpendicular coercivity of 2800 Oe and an excellent signal to noise ratio in read-write characteristics.