L10 FePtX–Y media for heat-assisted magnetic recording (Phys. Status Solidi A 7∕2013)




Heat-assisted magnetic recording (HAMR) is a new technology that will increase the achievable areal density in magnetic hard disk drives. In order to write bits into HAMR media, a laser locally heats beyond the Curie temperature and rapid cooling in the presence of the head field produces transitions in the magnetic orientation. Chemically ordered FePt exhibiting high magnetic anisotropy, will be used for the new thermally stable recording media. As discussed in the Review Article by D. Weller et al. (pp. 1245–1260), HAMR media are optimized by growing granular L10 FePt on a relatively thin thermal resistor seed layer on top of a thicker thermal conductor or heatsink layer. In addition soft underlayers are suggested to optimize the magnitude and angle of the magnetic write field. The achievable areal density depends on the near-field transducer dimension and the thermal conductivity of the media. Besides grain size, shape and distribution requirements, the thermal properties of both the magnetic and the seed layers need to be improved and optimized to achieve the required signal-to-noise ratio for higher areal densities in future magnetic recording, which will be in the range of 1.5-5 Tb∕in2.