次世代高密度磁気ディスク用単層グラフェン保護膜の提案

抄録

Heat-Assisted Magnetic Recording (HAMR) is expected as one of the future high density recording technologies. When FePt magnetic film for future recording material is heated at Curie temperature (Tc) around 850K (577 degree Celsius) with a near-field transducer (NFT), carbon overcoat film (COC) and lubricant film are also heated. Therefore, resistance for thermal damage of these thin films is much more requested than that for CoPt magnetic film (600K, 327 degree Celsius of Tc). We have examined a variety of COC materials by using new measurement systems, i.e. power scanning tool, based on surface-enhanced Raman spectroscopy (SERS). Our measurement tool composed of a transmission-type plasmonic sensor (TPS) can measure chemical structure of ultra-thin films with atomic scale with ultra-high sensitivity of 370,000 times greater than that of the normal Raman spectroscopy in magnitude. A variety of diamond-like carbon (DLC) films and graphene monolayer film have examined on critical temperature (CT) where the temperature at which intensity ratio of D peak to G peak (I(D)/I(G)) start increasing. As a result, best material is Graphene overcoat (GOC) with the CT of 1000 degree Celsius and more. The GOC is expected for higher recording density because of ultra-thin film (thickness of 0.3nm).