Microstructural Study of Electroless-Plated CoNiReP/NiMoP Double-Layered Media for Perpendicular Magnetic Recording

The microstructure of the electroless CoNiReP/NiMoP double-layered media was examined with various methods, focusing upon that of the in-plane anisotropy initial regions of the CoNiReP recording layers, and the origin of the initial region was discussed. It was confirmed that the initial region consists of randomly oriented fcc crystallites with Nirich composition, showing the granular condition, while the upper region with the perpendicular anisotropy consists of perpendicularly oriented hcp crystallites, forming the columnar structure with 20- to 30-nm diameter. It is considered that the formation of the initial region is due to a preferential deposition of Ni onto the NiMoP underlayers, and that the thickness of the initial region changes due to a change in the condition of the NiMoP underlayers, especially that of surface activity and/or morphology at their surfaces.