12 Gb/in/sup 2/ recording demonstration with SV read heads and conventional narrow pole-tip write heads

摘要

We have successfully demonstrated magnetic recording at areal densities as high as 12 Gb/in/sup 2/ at a data rate of 14/spl sim/15 MB/s using separate spin-valve read heads and narrow pole-tip inductive write heads on low noise Co alloy thin film disks. In this work, the nominal target densities were 350 Kbpi/spl times/34 Ktpi. To make these densities possible, large signal-to-noise gains were attained with the use of high performance spin-valve read heads and low noise thin film media. At the same time, very narrow track write heads were designed and fabricated by extending conventional photolithographic techniques. Finally, small magnetic spacings between the head and the disk were attained with low flying ABS designs and improved head and disk surfaces. Recording tests showed satisfactory writability and large readback signal of around 2 mV//spl mu/m. The 50% rolloff densities were as high as 10 Kfc/mm, while the write and read trackwidths were as narrow as 0.7 and 0.5 /spl mu/m respectively. An overall assessment of the parametric recording results indicated an areal density capability of at least 10 Gb/in/sup 2/. This projection was confirmed by error rate testing with an EPR-4 channel, where very low ontrack errors of 10/sup -10//spl sim/10/sup -9/ were achieved at 315/spl sim/380 Kbpi. Furthermore, squeeze measurements revealed well-defined 747 behavior with offtrack maxima at 0.7/spl sim/0.8 /spl mu/m trackpitch. The product of linear and track densities for the write and read head combinations tested indeed showed that an areal density of 11/spl sim/12 Gb/in/sup 2/ has been achieved.