R&D: Impact of Magnetic Medium Grain Height in HAMR

IEEE Magnetics Letters has published an article written by Yuwei Qin, and Jian-Gang Zhu, Data Storage Systems Center, Department of Electrical and Computer Engineering, Carnegie Mellon University, Pittsburgh, PA, USA.

Abstract: “Compared to conventional perpendicular magnetic recording, heat-assisted magnetic recording occurs at temperatures more than twice as high in degrees kelvin. The ability of head field to align the medium magnetization over the short duration in recording a bit is limited by the ratio of magnetic potential energy to the thermal energy. In this letter, we present a systematic micromagnetic modeling study of the transition jitter resulting from thermal agitation during the recording process. As we continue to decrease grain size in order to increase recording areal density, the height of grains in the recording medium needs to increase accordingly to keep the number of magnetization-misaligned grains to a minimum.“