Experimental Study of Nonlinear Transition Shift in Perpendicular Magnetic Recording with Single-Pole Head

Hiroaki MURAOKA  Yoshihisa NAKAMURA  

IEICE TRANSACTIONS on Electronics   Vol.E80-C   No.9   pp.1187-1193
Publication Date: 1997/09/25
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Issue on High Density Information Recording Technologies)
perpendicular magnetic recording,  single-pole head,  nonlinearity,  transition shift,  

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Nonlinear phenomena in perpendicular magnetic recording employing a single-pole head and a double-layered medium were investigated. First, measurement of linear superposition in the time domain indicated than the amount of nonlinear transition shift (NLTS) was less than 10 nm. It was concluded that the nonlinearity was caused by transition shift, not by waveform distortion. By interpreting the results, we proved that the NLTS was strongly related with head field gradient and interference field from recorded magnetization. Dependence on head parameter was examined by experiments. Based on the results, a single-pole head with which transition shift can be reduced was proposed. Pseudo-random sequence analysis revealed that NLTS was several percent even at 318 kFRPI, or at a bit interval of 80 nm, which agreed with the result of measurement of linear superposition in the time domain analysis. Experiments showed that NLTS increases the shortest bit length, in contrast with the case of longitudinal recording.