Breaking the thermally induced write error in heat assisted recording by using low and high Tc materials

TL;DR

This paper proposes a composite magnetic material with layers of different Curie temperatures to significantly reduce thermally induced write errors in heat-assisted magnetic recording, enabling higher data densities.

Contribution

Introduction of a novel composite structure with two magnetic materials to mitigate thermal write errors and increase recording density beyond previous limits.

Findings

Thermal write errors are negligible up to 50-100 Tbit/in2.

Composite structure reduces transition jitter.

Small Curie temperature distribution improves jitter performance.

Abstract

Heat assisted recording is believed as a key technology in order to further increase the areal density of magnetic recording. In the work of Richter et al. [Richter et al. J. Appl. Phys. 111, 033909 (2012)] it is stated that storage densities will be limited to 15 to 20 Tbit/in2 due to thermally induced write errors. In this letter we propose a composite structure consisting of two materials with different Curie temperatures. A hard magnetic layer is on top of a high Tc soft magnetic layer. In this composite material the thermal write error is negligible up to areal densities of 50 to 100 Tbit/in2. It is shown that the effective thermal field gradient, which is reduced in this composite structure, is not relevant for a possible increase of the transition jitter. The transition jitter is dominated by a small distribution of the Curie temperature. The smallest jitter is obtained for the composite structure.