Exchange-Biased Magnetoresistive Elements with Oxide Antiferromagnetic Thin Films

The corrosion resistance of an oxide antiferromagnetic NiO film and the exchange coupling between this film and Ni81Fe19 film were investigated for application to MR heads. The corrosion resistance of NiO film was superior to that of FeMn and Ni81Fe19 films. Bilayered 40 nm Ni81Fe19/100 nm NiO films had an exchange coupling field of about 20 Oe and blocking temperature of about 200 °C. An unshielded MR element was fabricated, on both sides of which patterned NiO films were placed. The magnetization pattern of Ni81Fe19 film which exhibited exchange coupling with the patterned NiO films on both sides showed a single domain state. Distortion associated with Barkhausen jumps was not observed in the MR response for the unshielded MR element nor in the reproductive waveform for a shielded MR head either.