Sensitivity study of 40 Gb/In2 recording systems to the fluctuation of head-disk spacing

As recording density reaches 40 Gb/in², the magnetic spacing fluctuation induced by head-disk contact will be high in comparison with its nominal value which is believed to be 11-14 nm. The relative high spacing variation has the potential to cause problems in the recording performance. In this paper, the variations of media noise, NLTS and servo burst alignment caused by mechanical spacing fluctuation are studied via micro-magnetic simulation, in terms of different writing currents. To constrain this kind of influence on the recording performance, both conventional longitudinal recording system and single layer perpendicular recording system, the current selection is more important