Areal density optimizations for heat-assisted-magnetic recording of high density bit-patterned media

TL;DR

This paper uses a detailed model to compare different HAMR strategies, finding that shingled HAMR with continuous laser pulses offers the highest potential for increasing storage density.

Contribution

It provides a comprehensive comparison of continuous versus pulsed laser spot recording and single versus bilayer grains in HAMR, optimizing for maximum areal density.

Findings

Shingled HAMR with continuous laser pulse yields the best results.

Bilayer grains with graded Curie temperature improve recording performance.

Optimized parameters significantly increase achievable areal storage density.

Abstract

Heat-assisted-magnetic recording (HAMR) is hoped to be the future recording technique for high density storage devices. Nevertheless, there exist several realizations strategies. With a coarse-grained Landau-Lifshitz-Bloch (LLB) model we investigate in detail benefits and disadvantages of continuous and pulsed laser spot recording of shingled and conventional bit-patterned media. Additionally we compare single phase grains and bits having a bilayer structure with graded Curie temperature, consisting of a hard magnetic layer with high $T_{\mathrm{C}}$ and a soft magnetic one with low $T_{\mathrm{C}}$, respectively. To describe the whole write process as realistic as possible a distribution of the grain sizes and Curie temperatures, a displacement jitter of the head and the bit positions are considered. For all these cases we calculate bit error rates of various grain patterns, temperatures and write head positions to optimize the achievable areal storage density. Within our analysis shingled HAMR with a continuous laser pulse moving over the medium reaches the best results, and thus having the highest potential to become the next generation storage device.