Spin-valve heads using CrMnPt antiferromagnetic films

Highly reliable spin-valve heads were developed using antiferromagnetic CrMnPt film. The exchange anisotropy energy J_K for CrMnPt/Co as-deposited film was almost the same as that for CrMnPt/NiFe film. However, the J_K doubled after annealing at a relatively low temperature of 230°C. The annealing causes distortion in the crystal lattice of CrMnPt films, which is likely to be the cause of the enhancement of the J_K. The MR ratio and the exchange coupling field of spin-valve films with a structure of Ta(5)/NiFe(5)/Co(1)/Cu(2.5)/Co(3)/CrMnPt(30)/Ta(5) (in nm) were 6.7% and 350 Oe, respectively. The CrMnPt-type spin-valve sensors are more resistant to electrostatic discharge (ESD) than IrMn-type spin-valve sensors. This is because of the higher blocking temperature of CrMnPt. The exchange coupling field H_UA in CrMnPt-type spin-valve sensors was thermally more stable than that in IrMn-type spin-valve sensors. Shielded spin-valve heads of a hard bias structure using CrMnPt antiferromagnetic film were fabricated. The readback waveform of the fabricated heads was noise-free and well biased. The output as normalized by the trackwidth was 800~1000 μV/μm. Spin-valve heads with CrMnPt were found to have an overall performance making them quite suitable for use in hard disk drives with an areal density higher than several giga bits/in²