Areal density limitation in bit-patterned, heat-assisted magnetic recording using FePtX media

The future evolution of magnetic recording data storage toward its ultimate limit is expected to involve a combination of energy-assisted recording on bit-patterned media, according to recent publications. In this work, we assess the effectiveness of single magnetic grain reversal under heat-assisted recording conditions by analyzing macrospin magnetization dynamics with the Landau-Lifshitz-Bloch equation. The simulations reported pertain to FePtX recording media and recording system parameters constrained by expected practical limitations. The approach adopted is assessment of the patterned media writing error rate as a function of applied bias field and areal density (AD), taking account of the relevant physics of the heat-assisted recording process. Additionally, we require that long-term thermal stability of recorded information be maintained, and that sufficient thermal and effective writing field gradients to support AD targets are available. For the long-time analysis, an Arrhenius-Nèel model of single grain switching probability is helpful. In this context, an investigation of achievable areal density with respect to tradeoffs in writing error rate at practical applied fields and thermal conditions is provided.