Magnetic Domain Structures of Multilayered Permalloy Films for Magnetic Recording Thin Film Heads

The domain structures of cores with patterned Permalloy films have been 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 10 ¿m. For six-layer Permalloy films with an alumina interlayer of 0.02 ¿m, domain patterns show that domain walls remain oriented along the direction of the track width, even for a width of 7 ¿m. Furthermore, six-layer Permalloy films with small anisotropy fields show no change in wall position when an external magnetic field is applied along the hard axis. It is thus concluded that six-layer Permalloy films with small anisotropy fields are most suitable for use in magnetic thin film heads with narrow track widths.