CoCrPt-alloy perpendicular media for high-density magnetic recording

CoCr-alloy perpendicular magnetic recording media have been investigated, as the Cr segregated structure in the CoCr-alloy recording layer is suitable for obtaining low noise properties. Recently, the grain size of the recording layer is required to be very small for high-density recording, therefore the thermal stability of the recorded bit is becoming a critical issue. The magnetic anisotropy should be improved to keep the thermal stability of the recording layer which consists of small grains. The addition of the Pt element and a decrease of Cr content are required in the CoCr-alloy. This, however, results in higher medium noise due to increasing inter-granular exchange coupling. In this paper, the effects of Cr content on the magnetic and recording properties in post-annealed CoCrPt-alloy perpendicular media were investigated. The post-annealing treatment is expected to enhance Cr diffusion into the CoCrPt grain boundary from a nonmagnetic CoCr intermediate layer.