Quantifying erasure and interference from adjacent tracks in heat-assisted magnetic recording

With track spacing in heat-assisted magnetic recording approaching the width of the reader and the thermal spot, the areal density capability is significantly penalized by interference and erasure from adjacent tracks. To quantify the impact, spin stand tests have been developed based on synchronous writing to capture the noise-free waveforms of the adjacent tracks and the partially erased data track, respectively. The results show that side reading interference from foreground adjacent tracks varies from 13 to 18 dB and strongly correlates with the effective reader width. Adjacent track erasure dominates at the edge of the data track, reduces its signal and increase its spatial noise. The signal loss and spatial noise increase scale with logarithm of the number of adjacent track writes. Measurements from two medium designs show such significant difference in adjacent track erasure that the ranking of their areal density capability is impacted.