垂直二層膜媒体における逆磁区ノイズ電圧の特徴化

Abstract

In perpendicular magnetic recording, medium noise characterization is necessary to improve head and disk performance, and to establish the signal processing strategy. We examined the medium noise of CoPtCrSiO2 perpendicular recording media with various SiO2 concentrations deposited by separating noise into transition jitter, pulse width breathing, and reversed domain noise. Since the reversed domain noise magnitude was small near transitions, the noise power decreased in proportion to linear density, and disappeared at densities higher than 200 kFCI. Thus, the signal–to–noise ratios at high linear densities were determined by jitter noise and pulse width breathing. Although the reversed domain noise increased for disks with higher SiO2 concentrations, error rate performance was improved. Therefore, the significant parameter was the transition jitter, and the influence of reversed domain noise was small.