Advanced heads for perpendicular recording at high areal densities and high data rates

Perpendicular magnetic recording at high areal densities and high data rates has been studied. Using ring heads and perpendicular media with soft underlayer, we have successfully demonstrated the areal density of 60 Gb/in/sup 2/ at the corresponding ultrahigh-linear density of 750 kbpi, a bit-aspect ratio (BAR) of 9.4, and a data rate of 300 Mb/s. Comparing the BAR of 5.7 in our recent 63.2 Gb/in/sup 2/ demonstration on longitudinal media, a larger BAR has been demonstrated with present perpendicular recording system. We have also demonstrated the data rate capability of 1 Gb/s by using both ring heads and modified-single-pole heads on perpendicular media with soft underlayer. Finally, a comparison of high-data-rate recording between ring heads and single pole heads has shown that neither magnetic viscosity nor gyromagnetic switching in perpendicular media is the limiting mechanism for magnetic recording at data rates as high as 1 Gb/s.