The frequency response of the magnetic field intensity and the phase angle was calculated by using threedimensional dynamic magnetic field analysis of thin-film heads. The frequency response of the magnetic field with thinner high-Bs core heads is better than that of conventional heads, because of the prevention of eddy current loss. It was found that the response of a head with a strong magnetic motive force is better than that of one with a weak magnetic motive force. This phenomenon is caused by magnetic saturation at the head core. This tendency becomes more marked with an increase of the write frequency. A head with a notch in the back gap region was also sutdied to prevent eddy current loss around the back gap. It was found thet a head with a notch is suitable for preventing eddy current loss around the back gap.
