Magnetic domain structures of multilayered permalloy films for magnetic recording thin film heads.

The domain structures of cores with patterned permalloy films are investigated in order to develop magnetic recording thin film heads with narrow track widths. For single layered permalloy films, domain patterns indicate that the writing and reading abilities decrease when the track width becomes less than 10μm. For six layered permalloy films with an alumina interlayer of 0.02μm thickness, domain patterns show that domain walls remain oriented along the direction of the track width even at the width of 7μm. Furthermore, six layered permalloy films with small anisotropy field show no change of wall positions when the external magnetic field is applied along the hard axis. It is thus concluded that six layered permalloy films with small anisotropy field are most suitable for magnetic recording thin film heads with narrow track widths.