MODEL FOR DEMAGNETIZATION-INDUCED NOISE IN THIN-FILM MAGNETIC
RECORDING MEDIA
Romney R. Katti
Venugopal V. Veeravalli
Mark H. Kryder
B. V. K. Vijaya Kumar
Abstract
A linear, statistical model is described which predicts the power
spectrum of measured noise in bulk-magnetized (i.e., ac-erased)
thin-film magnetic recording media. It is shown that the noise is the
result of magnetic flux which is ascribed to erasure-induced
transitions along the track in the medium. The noise power spectrum
for a rigid disk medium is shown to correspond to the power spectrum
of Poisson-distributed induced transitions along the track length,
while noise along the track width is sufficiently described in terms
of a uniform, average magnetization with small variance. Experimental
data from two thin-film disks are used with the model to estimate the
Poisson parameter for each disk. It is demonstrated that ac-erased
noise from particulate media can be considered as a limiting case of
the Poisson model.