R&D: Dependence of HAMR Transition Curvature on Bit Length

IEEE Transactions on Magnetics has published an article written by Kun Xue and R. H. Victora, Deparment of Electrical and Computer Engineering, University of Minnesota-Twin Cities, Minneapolis, MN 55455, USA.

Abstract: “Transition curvature is a major contributor to transition broadening in current HAMR devices. In this paper, in order to clarify HAMR performance versus bit length, a detailed study of the dependence of HAMR transition curvature on bit length is presented. With the help of micromagnetic simulations, HAMR bits with three different bit lengths (10.5, 15, 21nm) are written and transition curvatures are calculated. Both thermal ECC media and pure FePt media are tested. By tracking the change of transition curvature during the HAMR cooling process, an erase-after-write effect is observed. DC-erased media, intergranular exchange and removal of dipole interactions are also examined for potential optimization of the HAMR system.“