Submicron-trackwidth inductive/MR composite head

To explore the possibility for ultra-high areal density recording, submicron-trackwidth inductive-write/magnetoresistive-(MR)-read composite heads were fabricated. The focused ion beam etching technique was applied to fabricate a ~1-μm-wide write-track completely aligned to the read-region of the MR sensor. The write head using multilayered Fe-based alloy pole pieces with a saturation magnetization of 2.0 T revealed sufficient writability and excellent frequency response. A shunt-biased MR sensor having a narrow gap-length operated at a high current density over 3×10⁷ A/cm² is developed to reproduce a sufficient signal amplitude at high linear-density regions. Recording tests were carried out on a thin-film medium with a head-medium clearance of 0.05 μm. The output voltage per micron of trackwidth over 400 μV with symmetrical pulses, and a -6-dB rolloff density of around 90 kFCI were measured. The design procedure, fabrication method, and recording performances of the submicron-trackwidth inductive/MR composite heads which can attain 2 gigabits recording are discussed