Effects of very thin carbon seedlayer on formation of hcp phase for CoCrPtB/Co/sub 60/Cr/sub 40/ perpendicular magnetic recording media

Abstract

This paper reports on significant improvement of magnetic properties for CoCrPtB/Co 60 Cr 40 perpendicular recording media by utilizing very thin C seedlayer even with the thickness of less than 1 nm. This is caused by the following microstructural characteristic: 1) the C seedlayer, heated to higher than 200 C, reacts with CoCr intermediate layer, and results in the formation of nanocrystalline layer with the thickness of about 6 nm; 2) Cr-deprived hcp grains with Cr segregation structure grow on the nanocrystalline layer without forming -phase grains in the intermediate layer; 3) CoCrPtB magnetic layer epitaxially grows on the intermediate layer without forming initial layer, which behaves as soft ferromagnetic layer and degrades magnetic properties of the media. Index Terms--phase, Co 60 Cr 40 intermediate layer, epitaxial growth, very thin C seedlayer.