Effects of media orientation on noise, track width, and thermal relaxation

A set of longitudinal antiferromagnetically coupled media with different orientation ratios (OR) was used to study the dependence of recorded data on OR. The OR dependence of dc and transition noise was investigated using a position-dependent time-domain technique. It is shown that both dc and transition noise decrease for a higher medium OR. A model for the dc erase noise power dependence on OR is developed. We will demonstrate that a medium with lower OR has a larger baseline shift and larger effective track width due to an increased cross-track magnetization component at the track edges. A strong dependence of media relaxation time on medium OR was discovered with slower decay rates for higher OR media. These slow relaxation times give rise to anomalous track profiles with track tails extending over 2 microns away from the track center.