Spin-valve read heads for tape applications

Shielded spin-valve tape heads with permanent magnet stabilization are described. Final MR of 3.5% is shown on heads with trackwidths of 5 and 9 μm, and sensor heights of 0.5, 1.0 and 1.5 μm. Heads are characterized on ½" DLT-IV tape up to 180 kfci. For isolated transitions the heads show a PW₅₀ of 0.8 μm (pulse broadening due to partial head saturation) and a baseline shift ~10% that can be positive or negative, and is related with shield remanence and transfer curve hysteresis. At 120 kfci, head output for a sense current of 3 to 4 mA is ~1 mV_pp (up to 30% of the output at 30 kfci). At high linear densities, signal loss is 0.24 dB/kfci for a 0.35 μm shield-to-shield spacing (D₅₀ of 80~100 kfci). At low linear densities the head is partially saturated, and above 60 kfci harmonic distortion is lower than -20 dB