Landau–Lifshitz–Gilbert (LLG) simulation [17] showed that the combination of an advanced head with high write field and field gradient, such as shown in Fig. 4, [16], and the BPM with the anisotropy field dispersion of 5% and a 3 deg easy axis dispersion can actually support around 4 Tb/in . However, in the absence of thermal or microwave assisted recording, an areal density of around 5 Tb/in could barely be supported by the medium with unrealistically small dispersions. This may suggestsupportofenergy assistedrecordingtechnology willbe required for BPMR beyond around 5 Tb/in . Traditional lithography techniques used in semiconductor processing will be inadequate to produce BPM with feature