# Systematic parameterization of heat-assisted magnetic recording switching probabilities and the consequences for the resulting SNR

## TL;DR

This paper develops an analytical model to evaluate how material properties and parameters in heat-assisted magnetic recording influence switching probabilities and SNR, providing insights for optimizing recording media.

## Contribution

It introduces a comprehensive analytical model linking material parameters to SNR in HAMR, enabling systematic optimization of recording performance.

## Key findings

- SNR increases by ~10dB with certain parameter adjustments
- Switching probability improvements significantly enhance SNR
- Model shows good agreement with theoretical formulas

## Abstract

The signal-to-noise ratio (SNR) of a bit series written with heat-assisted magnetic recording (HAMR) on granular media depends on a large number of different parameters. The choice of material properties is essential for the obtained switching probabilities of single grains and therefore for the written bits' quality in terms of SNR. Studies where the effects of different material compositions on transition jitter and the switching probability are evaluated were done, but it is not obvious, how significant those improvements will finally change the received SNR. To investigate that influence, we developed an analytical model of the switching probability phase diagram, which contains independent parameters for, inter alia, transition width, switching probability and curvature. Different values lead to corresponding bit patterns on granular media, where a reader model detects the resulting signal, which is finally converted to a parameter dependent SNR value. For grain diameters between 4 and 8nm, we show an increase of ~10dB for bit lengths between 4 and 12nm, an increase of ~9dB for maximum switching probabilities between 0.64 and 1.00, a decrease of ~5dB for down-track-jitter parameters between 0 and 4nm and an increase of ~1dB for reduced bit curvature. Those results are furthermore compared to the theoretical formulas for the SNR. We obtain a good agreement, even though we show slight deviations.