Structure and Magnetic Properties of Sendust/Under-Layer Films

Sendust MIG (metal-in-gap) heads have been developed for use in high density recording systems. Al oxidization at the boundary between the Sendust film and the MnZn-ferrite, however, acts to degrade the soft magnetic properties, and insertion of Ni-Fe film between them is an effective way to rectify the problem. In the present paper, the effects of Ni-Fe film insertion are investigated in detail, with the following results: 1) X-ray diffraction intensity from the (110) plane is stronger for Sendust film on Ni-Fe/MnZn-ferrite than for MnZn-ferrite. 2) Ni atoms in the Ni-Fe film diffuse into the Sendust film with annealing at 550°C and over. 3) Little degradation of the permeability and coercivity is observed for Sendust film containing less than 1.4-wt% Ni.