Rigid disk medium for 20 Gb/in(2) recording demonstration

A longitudinal medium was developed for 20 Gb/in(2) recording. This medium has a coercivity of 3380 Oe and M(r)delta = 0.42 memu/cm(2). Modulation noi se and track edge noise were well suppressed by the decrease in the activat ion volume. Remanent magnetization is stable; at 338 K, the coefficient of remanence reduction was -0.066 dB/decade in a reverse field of 460 Oe which corresponds to the demagnetizing field in a bit at 430 kFCI, Recording bit s of 430 kfci were confirmed by MFM, The BER was 3.45x10(-6) using a conven tional EPR4 channel with a 16/17 code rate at 405 kBPI (430 kFCI). From squ eeze measurements, the track pitch was 0.505 mu m (50.3 ktpi) including a g uard band of 0.06 mu m. 20.4 Gb/in(2) recording is made possible by the com bination of a narrow gap spin-valve head and a low noise medium.