Magnetic Properties of Narrow Stripe Co-Ta-Zr Amorphous Films

The magnetic properties of narrow stripe Co-Ta-Zr amorphous films, with induced anisotropy across the stripe width, have been investigated. The permeability of the films decreases with decreasing stripe width. This can largely be explained by the increased demagnetization field which may reduce the initial anisotropy and rotate the easy axis to a direction perpendicular to the initial easy axis, or may change the magnetic domain structure. Stress in the film may act to enhance or retard this effect, depending on the film´s magnetostriction constant. It is therefore important to determine an appropriate magnitude for the induced anisotropy and to choose a proper combination of the magnetostriction constant and the substrate thermal expansion coefficient. Utilizing such knowledge, thin film heads with a 5 ¿m track width have been fabricated. A reproduced voltage of 380 ¿VPP/mm-turn-m/s has been obtained in combination with Co-Cr perpendicular recording medium.