HAMR Versus PMR: A Comparative Study of Signal-Noise Performance

A micromagnetic simulation-based comparative study between perpendicular magnetic recording (PMR) and heat-assisted magnetic recording (HAMR) has been performed. Signal-to-noise ratio (SNR) is adopted as the metric of comparison, and various system parameters are considered, including fly-height (FH), write-track distance, and rotary motion of the head-stack-assembly (skew). It is found that even a HAMR system with a wide 60 nm full-width at half-maximum thermal profile demonstrates better SNR performance when compared to an optimized PMR system at a magnetic FH of 8 nm. The impact of skew on a single reader system is found to be minor for both PMR and HAMR, but the impact on a dual reader 2-D recording system differs substantially. In particular, the resolution for small bit detection depends greatly on reader shield orientation to the HAMR-written curved transition beneath the read free layer.