Impact of straightened thermal profiles generated by gapped near field transducers on HAMR SNR

In this work, heat assisted magnetic recording (HAMR) is simulated to assess the areal density advantages of various realistic thermal profiles. Specifically, finite element simulation and micromagnetic modeling are used to assess the areal density consequences of a straighter thermal profile with an associated wider track. This assessment is done by simulating the thermal profiles created by heads with gapped near field optical transducers (NFTs) and split magnetic poles. By varying the gap width of the NFT and the thickness of the medium interlayer, the above variation in transition straightness and associated written transition is achieved. At specific operating points, we find that a wider track with a straighter transition results in a slightly higher recording density (1.2Tb/in2 vs 0.9 Tb/in2). As expected, the former case finds its optimum at higher linear bit densities (1370 kFCI) and lower track densities (850 kTPI) than the latter case (870 kFCI and 1000 kTPI).