Magnetic properties of amorphous Co-Hf-Pd and -Pt alloys for thin film heads

The magnetic properties of amorphous Co-Hf-Pd and -Pt films prepared by sputtering have been investigated. We have found that there is a wide range of composition which has both high Bs of 14 to 15 kG and low positive λs of the order of 10^-7. The amorphous Co-Hf-Pd and -Pt films with λs lower than +1×10^-6have high permeability μm after rotating magnetic field annealing. The crystallization temperature Tx of amorphous Co-Hf-Pd and -Pt films depends on the Hf content. Amorphous Co-Hf-Pd and -Pt films with Bs of 15 kG have been applied to the main pole of single-pole type heads in perpendicular magnetic recording, resulting in high reproduced voltage and high overwrite S/N. We have determined that Barkhausen noise can he eliminated by using the main pole film with λs of the order of 10^-7.