4.8 nm diameter Ru grains grown on a large-grain seed layer for perpendicular magnetic recording media

Abstract

A concept for the non-magnetic intermediate layer (NMIL) is proposed, which realizes a recording layer of small and highly c-plane oriented grains with no inter-granular exchange coupling. The NMIL consists of three individual epitaxially grown functional layers: a large-grain seed layer (SL) with a highly oriented sheet texture, a first inter-layer (IL1) of small grains and a second inter-layer (IL2) of segregated non-magnetic grains. On focusing on the wettability and the lattice misfit of Ru IL against the SL material, the Mg SL is found to realize the small Ru grains of 4.8 nm diameter retaining a small orientation distribution of 4.1°.

The Influences of Ru Seed Layer Microstructure on Structural Properties of CoCrPt-SiO₂ Perpendicular Media

“…Low media noise are crucial properties to perpendicular media, and grain isolation is important to improve media noise performance, CoCrPt-SiO 2 perpendicular films which have very fine grains with nonmagnetic SiO 2 at the grain boundary effectively decrease inter-granular exchange coupling to achieve low media noise and high perpendicular anisotropy, thus CoCrPt-SiO 2 granular film is well known as a perpendicular magnetic recording(PMR) media. In CoCrPt-SiO 2 granular-type perpendicular magnetic recording media, Ru is used as an underlayer to induce perpendicular anisotropy of the recording layer due to heteroepitaxial relationship between Ru (002) and CoCrPt (002) [5][6][7][8].…”