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A recording density of 106 Gbits/in2 has been achieved using a high-sensitivity spinvalve head [ 11 and a thermally stable synthetic ferrimagnetic medium (SFM) [2]. The use of a highly stable medium allowed the demonstration to be made with a bit aspect ratio of 5.3 which is higher than the projected value of 4. Table I lists some selected parameters for the demonstration.The read head is a double specular spin-valve with greatly improved MR performance, large exchange bias field, and low coercivity. The write head consists of iaminated high Bs (> 2 Tesla) poles. The write yoke was trimmed by a dry etch process.The SFM is an oriented medium consisting of two antiferromagnetically coupled layers of advanced CoCrPtB alloys. The stabilization layer thickness is 5 nm and the main recording layer is 15 nm-thick. The stability factorKuVkT is 58 and the signal decay at 590 KFCI was measured to be less than O.l%/decade at room temperature. Table I. Selected Parameters Figure 1 shows the on-track error rate at a linear density of 750 KBPI after ECC and Figure 2 shows the indicating a track pitch of 142 KTPI. These areal density of 106 Gbitshn2.parameters suggest a percolation linear density of over 1000 KBPI which make densities above 140 Gbitdin2 seem feasible.Estimates using the demonstration head and medium [ 13

A bstruct -We developed an integrated-Viterbidetector which can handle PRML and EPRML. Both PR4 and EPR4 equalization can be accepted according to the recording density. The EPRML performance is superior to that of PRML for a normalized recording density above 1.8, but inferior at lower densities. Our experimental results agree with theoretical values and prove that the performance of this Viterbi detector is superior, by 8 dB, to that of conventional peak detectors when the normalized recording density is 2.7.