Fabrication and electrical properties of lapped type of TMR heads for ∼50 Gb/in2 and beyond

Tunnel giant magnetoresistance (TMR) heads at ∼50 Gb/in² have been fabricated using improved lapping process. Together with writer of 2.0 T pole materials, recording performance has been demonstrated at magnetic write width of 0.28 μm and magnetic read width of 0.18 μm. The resistance area product of final wafer data is around 5 Ω·μm², with lead and contact resistance included, resulting in a final head resistance of around 200 Ω. The output voltage achieved for 1 mA bias current is 42 mV/μm, and the isolated pulses are stable. With a discrete preamplifier, the track density as measured by "747 curve" is 94 kTPI at a bit-error rate of 10^-4 and the linear density is 508 kBPI, achieving an areal density of 48 Gb/in². The noise analysis reveals that the noises come mainly from media and shot noise.