Understand SNR limit and area density capability in HAMR

Heat, or thermal, assisted magnetic recording (HAMR or TAMR), has become a strong candidate as the new recording scheme for future hard disk drive technology. In depth understanding the detailed recording processes and the performance correlation with all the important recording parameters and medium properties is of critical importance for the practical realization of its intended advantages at ultra-high area recording densities. This paper is dedicated to this purpose and the study is carried out via micromagnetics based recording simulation, utilizing the Landau-Lifshitz-Bloch Equation for modeling the medium behavior near Curie temperature. The medium is a single magnetic layer of FePt-Llo grains with non-magnetic grain boundaries. For clarity purpose in recording analysis, the thermal profile of the heating spot is assumed to be Gaussian in the down track direction and uniform in the cross-track direction so transition front will be straight rather than curved. The recording head field is assumed to be spatially uniform at a fixed angle of 45° with respect to the perpendicular axis. Thermal agitation field to each magnetic grain is included in simulating the recording process, according to the fluctuation-dissipation theorem.