Laminated dual-axial anisotropy film for submicrometer-trackwidth thin-film heads

A dual-axial anisotropy film which consists of two uniaxial sandwiches of Co₉₁Nb₆Zr₃/SiO₂/Co₉₁ Nb₆Zr₃ with their easy axes orthogonally oriented, was fabricated by RF-sputtering using a water-cooled, magnetic substrate holder, for application in a new type of submicron trackwidth thin film head. The thermal stability of the induced uniaxial anisotropy of the film was studied by heat treatment in a magnetic field and subsequent magnetic measurements. The magnetic properties of the films before and after rotational field annealing (RFA) mere studied by their B-H loops and permeability spectrum along various directions in the film plane. It was found that the B-H loops of the as-deposited dual-axial film along either axis were the superposition of the easy axis and hard axis B-H loops of the two uniaxial sandwiches along that axis. The two uniaxial sandwiches appear to behave independently before RFA. In-plane isotropic B-H loops and isotropic permeability of 2640 at 10 MHz were obtained for the dual-axial films after RFA at 320°C. The small H _k and the magneto-static interaction between the two sandwiches may be mainly responsible for the isotropic magnetic properties of the dual-axial film after RFA