Grain size reduction and recording performance improvement by using NiW as a partial interlayer in CoCrPt/SiO2 recording medium

We report the effect of NiW, as an interlayer to partially replace Ru, on the microstructure, magnetic properties, and recording performance of CoCrPt/SiO2 perpendicular recording media. It was found that the full width at half maximum of the rocking curves of the Co (0002) peak changed little with NiW thickness up to 10 nm. However, further increase of NiW thickness caused a larger c-axis dispersion. The grain size of the CoCrPt/SiO2 recording layer was reduced from 10.9±1.8 nm for the films without NiW to 7.7±1.5 nm for films with 10-nm NiW as a partial interlayer. The coercivity, Hc, nucleation field, Hn, and the reverse overwrite, Rev_OV, of the CoCrPt/SiO2 layer did not change much (less than 15%) with increased NiW thickness. However, it did affect the switching field distribution of the CoCrPt/SiO2 layer (more than double). The recording performance was improved by using NiW as a partial interlayer, which was mainly attributed to the reduced grain size.