Longitudinal and perpendicular magnetic thin film media noise

Abstract

Comparison of the magnetic media noise measured for perpendicular and longitudinal Co-Cr media producing the same signal amplitude indicates that the perpendicular media noise is smaller than the longitudinal media noise in both the kilohertz and the megahertz frequency spectra. A simple theory based on magnetic domain wall distortion is presented which yields results that are consistent with these experimental observations. Whereas previous researchers have measured a 6 dB difference in the megahertz range, we have found that the perpendicular recording media noise is at least 2 to 3 dB lower than the longitudinal recording media noise in the kilohertz range.