Microstructure and magnetic properties of FePt-(C,SiO2) granular films deposited on MgO, MgTiO, and MgTiON underlayers

We investigated the microstructure and magnetic properties of FePt-(C,SiO2) granular films deposited on MgO, MgTiO, and MgTiON underlayers. The coercivity and grain size of the FePt-(C,SiO2) film are substantially degraded when deposited on the MgTiO underlayer compared to those on the MgO underlayer, while they become comparable when deposited on the MgTiON underlayer. Atomic resolution STEM-EDS showed Ti in the MgTiO underlayer diffuses into FePt grains, while it is suppressed using the MgTiON underlayer. This suggests that MgTiON is a good choice for a conductive underlayer for growing L10-FePt perpendicular recording media for heat assisted magnetic recording.