Far-field head-media optical interaction in heat-assisted magnetic recording

TL;DR

This paper theoretically investigates the far-field optical interactions in heat-assisted magnetic recording, highlighting the impact of interlayer thickness on media reflection and absorption, with results validated by experiments.

Contribution

It introduces a plane-wave expansion method to analyze optical interactions in HAMR media, revealing the sensitivity of absorption to interlayer thickness changes.

Findings

Interlayer thickness significantly affects media reflection and absorption.

A 10-nm change in interlayer thickness alters absorption by over 25%.

2-D model results align well with 3-D simulations and experimental data.

Abstract

We have used a plane-wave expansion method to theoretically study the far-field head-media optical interaction in HAMR. For the ASTC media stack specifically, we notice the outstanding sensitivity related to interlayer's optical thickness for media reflection and magnetic layer's light absorption. With 10-nm interlayer thickness change, the recording layer absorption can be changed by more than 25%. The 2-D results are found to correlate well with full 3-D model and magnetic recording tests on flyable disc with different interlayer thickness.