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/lambda (dB) at densities over 100kFRPI and at small spacings below 0.1-mu-m. The error rate was measured to evaluate the disk drive operation at a head-to-medium spacing of 340 angstrom. The error rate of 10(-9) and the phase margin of 40% were achieved at 100kFRPI and 100-mu-m trackwidth without an equalizer. Furthermore, the error rate of 10(-9) was obtained at 110kFRPI and 100-mu-m trackwidth, or at 60kFRPI and 6-mu-m trackwidth, using a cosine equalizer introduced to reduce the pattern peakshift.