Recording performance of CoCrPt-(Ta, B)/TiCr perpendicular recording media

The magnetic properties, microstructure and the recording performances of CoCrPt-(Ta, B)/TiCr perpendicular magnetic recording media were studied in conjunction with the effect of thermal agitation. The addition of Th or B to CoCrPt media significantly improves its low noise performance, mainly due to the reduction of grain size and intergranular magnetic interactions. However, adding Ta or B also reduces the value of perpendicular magnetic anisotropy, K-u, especially in the initial growth layer, resulting in the degradation of thermal stability. In order to achieve high thermal stability without degrading the low noise performance of these media, an M-r/M-s value of nearly 1.0 is required. This may be achieved by suppressing of the reduction of K-u and the reducing intergranular magnetic interactions, whilst maintaining their small grain size.