EFFECTS OF BORON ADDITION TO UNDERLAYER FOR COCRPT MEDIA ON MAGNETIC CHARACTERISTICS AND MICROSTRUCTURE

Magnetic and recording characteristics of CoCrPt media with a CrTiB un derlayer was investigated, Higher coercivity He and coercive squarenes s S were obtained compared with the media that had a CrTi underlayer. The overwrite property of the media was also improved by adding boron , while the change in media noise was very small. Transmission electro n microscopy analysis showed that the crystal grain-size dispersion in the magnetic layer was reduced by about 15% when boron was added to t he underlayer, and the average grain size was almost the same as when the CrTi underlayer was used. The higher S and improved overwrite pro perty that resulted when using a CrTiB underlayer should be attributed to the reduction in the grain size dispersion, which provides a narro wer switching field distribution.