Reduction of medium noise of Co-Pd multilayered perpendicular magnetic recording media by a thin carbon interlayer

We report the effect of introducing a thin carbon interlayer to the recording layer on the read-write characteristics of Co-Pd multilayered perpendicular magnetic recording media. A 1-nm-thick carbon interlayer markedly reduced the medium noise and improved the output resolution, D₅₀. As a result, the signal-to-noise ratio at the recording density of 200 kFRPI for the medium was higher by 5 dB than that for the medium without the interlayer. We attribute these improvements in read-write characteristics to a decrease in the crystal grain diameter of the recording layer, resulting in suppression of the transition fluctuation of recorded bits. The Co-Pd multilayered perpendicular magnetic recording medium with carbon interlayer has a high thermal stability despite a slight degradation of perpendicular magnetic anisotropy.