In order to develop an in-line dual gap thin film head for the video floppy system, magnetic annealing influences on the characteristics of CoNbZr amorphous thin films were investigated. It was revealed that the magnetic anisotropy fields decrease and both the initial permeability parallel to the easy axis and the one perpendicular to it increase as the annealing temperature increases and that the magnetic anisotropy fields change to isotropic and the initial permeabilities perpendicular to the easy axis decrease when the magnetic annealing temperature rises above 460°C. The upper core and the lower one of the head from a closure magnetic domain with the easy axis parallel to the gap width. The output levels of the head are strongly affected by the initial permeability parallel to the easy axis. The thin film in-line dual gap magnetic head having excellent characteristics was develoed by means of the magnetic annealing of CoNbZr amorphous films.
Behavior of characteristics in CoNbZr amorphous thin film heads by magnetic field annealing is investigated by observing the domain patterns. Two step magnetic field annealing in which the magnetic field is applied first perpendicularly to the preferable easy axis and secondly in parallel with it, is found to be effective to improve the characteristics of the heads.