# Efficiently reducing transition curvature in heat-assisted magnetic recording with state-of-the-art write heads

## TL;DR

This paper presents a novel heat-assisted magnetic recording head design that significantly reduces transition curvature and jitter, improving data read-back quality on granular media by up to 40%.

## Contribution

It introduces a new head design and simulation approach to effectively minimize transition curvature in HAMR, enhancing recording precision.

## Key findings

- Transition curvature reduced by up to 40%
- Improved transition jitter in multiple directions
- Effective head design based on LLB model

## Abstract

The curvature of bit transitions on granular media is a serious problem for the read-back process. We address this fundamental issue and propose a possibility to efficiently reduce transition curvatures with state-of-the-art heat-assisted magnetic recording (HAMR) heads. We compare footprints of conventional with those of the proposed head design on different media, consisting of exchange coupled and single phase grains. Additionally, we investigate the impact of various recording parameters, like the full width at half maximum (FWHM) of the applied heat pulse and the coercivity gradient near the write temperature of the recording grains. The footprints are calculated with a coarse grained model, based on the Landau-Lifshitz-Bloch (LLB) equation. The presented simulations show a transition curvature reduction of up to 40 %, in the case of a medium with exchange coupled grains and a heat pulse with a FWHM of 40 nm. We further give the reason for the straightening of the bit transitions, by means of basic considerations with regard to the effective recording time window (ERTW) of the write process. Besides the transition curvature reduction the proposed head design yields an improvement of the transition jitter in both down-track and off-track direction.