Spatial noise phenomena of longitudinal magnetic recording media

The authors have studied the spatial noise characteristics of uniformly magnetized media and implemented a synchronous magnetic pulse detection technique to measure waveforms from precise radial and azimuthal locations on a magnetically recorded disk. They introduce a correlation analysis which includes measuring noise waveforms from the same position on the disk under different remanent magnetic states. Results from this analysis demonstrate that at remanence only minor changes occur in the output waveform and its (presumed) corresponding magnetic structure from write to write, while at DC demagnetization large variations are seen for successive writes. This sensitive correlation technique is used to analyze the random and deterministic components of media and head noise