次世代超高記録密度磁気ディスク用単層グラフェン保護膜と潤滑膜の化学構造解析

抄録

Decreasing head/medium spacing and Heat-Assisted Magnetic Recording (HAMR) are key issues for achieving future high density hard disk system. Single graphene (SG) film is the most promising material for those technologies because of monomolecular thickness around 0.3 nm, large heat resistance for FePt magnetic recording medium (850K, Curie temperature) and high shield performance against migration of Co or Fe ions which causes creation of smear. However, single crystal graphene film is basically inert with weak bonding to substrate and lubricant. In this report, we examined new lubricants, perfluorinated poly ether (PFPE) with OH and phenyl groups for some graphene materials, i.e. single crystal graphene, graphene oxides (GO), or SG film on CoPt using surface-enhanced Raman spectroscopy (SERS) with new optical device, i.e. transmission-type plasmonic sensor. The lubricant exhibits good bonding performance to defect structures in graphene oxide through phenyl groups, Defect structures are composed of dangling bonds or oxidated carbon. Thermal resistance of the lubricant on GO increases compared with non-bonding lubricant on SiO₂. According to the depth profile of Raman spectra around interface between SG film/CoPt medium, the SG film adheres to the CoPt medium through Co hydroxide.