Design and read performance of GMR heads with NiO

GMR heads with NiO/NiFe/Co/Cu/NiFe films have been designed, fabricated, and their read performance was tested. Calculations showed that output was reduced significantly when the exchange coupling field on the pinned layer was smaller than 200 Oe due to tilting of the magnetization of the pinned layer. When the pinned layer of NiFe(1 nm)/Co(1 nm) was used, the coupling field from NiO was 360 Oe which would be large enough to ensure the full output. The readback waveform of the fabricated head was noise-free and well biased. The obtained output was about six times as large as that of conventional AMR head. When the sensing current was increased, the output increased linearly up to the current density of 20 MA/cm², while the peak asymmetry was not affected much by the current. The output increased linearly with the read width, except for small dead zones at both of the track. The microtrack profile was symmetric, reflecting the symmetric magnetization configuration of the free layer without the medium field