High areal bit density perpendicular magnetic recording on hard disk

The feasibility of high-areal-density perpendicular magnetic recording was investigated in a hard disk system using a contact-type single-pole head and a Co-Cr/Ni-Fe medium. The overall spacing loss in recording and reproduction processes was found to be 100 to 110 d /λ (dB) at densities over 100 kFRPI and at small spacings below 0.1 μm. The error rate was measured to evaluate the disk drive operation at a head-to-medium spacing of 340 Å. An error rate of 10^-9 and a phase margin of 40% were achieved at 100 kFRPI and 100-μm trackwidth without an equalizer. Furthermore, an error rate of 10^-9 was obtained at 110 kFRPI and 100-μm trackwidth, or at 60 kFRPl and 6-μm trackwidth, using a cosine equalizer introduced to reduce the pattern peakshift