Abstract
Fe-Co and Fe-Co-Al-O films were prepared by RF magnetron sputtering in Ar gas atmosphere. An Hch (coercivity in the hard axis direction) value of 11 Oe (0.88 kA/m) was obtained for an Fe-Co film by choosing proper sputtering condiition. Hch was greatly decreased by using Al2O3 addition of 1% and a Ni-Fe underlayer of 0.5-12 nm, resulting in a value less than 1 Oe (80 A/m) for a film thickness range from 50 nm to 600 nm. Amorphous Co-Zr-Nb soft magnetic underlayer films are also effective for obtaining Hch values less than 1 Oe (80 A/m). It is finally concluded that combination of a small amount of Al2O3 addition and a soft magnetic underlayer film is essential for obtaining low Hch with high saturation magnetic flux density of 2.4 T in a wide range of film thicknesses.
