COMPOSITIONAL MICROSTRUCTURES OF COCR-ALLOY PERPENDICULAR MAGNETIC RECORDING MEDIA

Compositional microstructures of CoCrTa and CoCrPt perpendicular magne tic recording media are investigated using a high resolution transmiss ion electron microscope equipped with an imaging filter. In the CoCrTa film, clear Cr segregation at grain boundaries is recognizable. The C r-enriched layer is analyzed to be paramagnetic phase of which Cr conc entration is greater than 30 at%. In the case of CoCrPt film, Cr segre gation is observed within the grains, and the Cr contents at grain bou ndaries are far lower than those measured for the CoCrTa film. The dif ference in the compositional microstructure is related to the differen ce in noise characteristics of CoCrTa and CoCrPt media.