Effect of track edge erasure and on-track percolation on media noise at high recording density in longitudinal thin film media

In this work the experimental evidence of the effect of track edge erasure and on-track percolation on media noise is investigated using Magnetic Force Microscopy (MFM) for CoCrTaPt/Cr thin films deposited at different substrate temperatures (T-s). As the recording density increases from 60 to 146 kfci, the track edges begin to erase and the effective track width reduces, causing a subsequent drop in the read back signal and increase in media noise. Also with the increase in recording density the bit length reduces and the transition boundaries get closer to each other. As a result, the transition boundaries are no longer sharp and show onset of percolation. The onset of on-track percolation for films deposited at 160 degrees C with higher exchange interaction occurs at lower recording density compared to the film deposited at 235 degrees C. The track edge percolation occurs at lower recording density than the on-track percolation for both samples.