A HAMR Media Technology Roadmap to an Areal Density of 4 Tb/in$^2$

摘要

This paper discusses heat-assisted magnetic recording (HAMR) media requirements and challenges for areal densities (AD) beyond $1~hbox{Tb/in}^2$. Based on recent roadmap discussions the focus is primarily on granular chemically ordered ${rm L}1_0$ FePtX-Y-perpendicular media with reduced average grain size down to $langle{rm D}rangle=3hbox{-}5~hbox{nm}$ relative to current CoCrPt based perpendicular magnetic recording (PMR) media with average grain size $langle{rm D}rangle=7hbox{-}9~hbox{nm}$. In HAMR media the combination of thermal conductivity and Curie temperature ${rm T}_{rm C}$ determines the required laser power during recording. Key challenges are sigma variations of D and ${rm T}_{rm C}$ which need to be reduced to $sigma_{rm D}/{rm D}sim 10hbox{-}15%$ and $sigma_{rm TC}/{rm T}_{rm C}sim 2%$. In addition AD is limited by switching field distribution (SFD) and thermal spot size. The key goal going forward is to optimize heads, media, head-media-spacing (HMS) and read-back channel technologies to extend AD to $4~hbox{Tb/in}^2$ and beyond.