5 Gb/in2 recording with dual stripe AMR heads and low noise thin film disks

We have demonstrated magnetic recording at an areal density of 5 Gb/in² using dual stripe magnetoresistive heads (DSMR) on low noise and low-glide height quaternary CoCrTa-based alloy thin film disks. The data rate is 120 Mb/sec with a PR4 channel, and the on-track error rate achieved is around 10^-9. The demonstration was accomplished in two cases using two different types of heads. In the first case, it was done with a DSMR head having shield-shield spacing of 0.165 μm and 1 μm stripe height flying at 25 nm, resulting in a linear density of 321.7 KBPI, and a track density of 15.6 KTPI. The second case was performed with DSMR heads having shield-shield spacing of 0.18 μm and 8 μm stripe height flying at proximity height of 12 nm, achieving a 358.75 KBPI and 13.8 KTPI. This is the highest linear density published so far for either GMR or AMR heads. It is the direct consequence of high signal/noise of DSMR heads and proximity recording over low noise, low-glide-height media. To explore the large dynamic range of DSMR heads, this study was also done with a variety of low noise disks with Mrt ranging broadly from 0.45 to 1.0 memu/cm² and coercivity of 3000 Oe