Effect of Side-Fringing Field on Read-Write Characteristics for Thin Film Magnetic Heads

The side-fringing fields of thin film heads were studied using three-dimensional simulations. Playback signals were calculated using the reciprocity principle. The output as a function of linear density was calculated by superpositioning of isolated pulses. The results of three-dimensional calculations of isolated pulses, off-tracking and output as a function of linear density, agreed with measurements. These calculations and measurements indicated that the effect of the side-fringing field appears in the isolated pulses from narrow-track heads. It was found that asymmetry in isolated pulses results from the effect of the side-fringing field. By narrowing the track width, the effect of the side-fringing field is increased. Playback pulses from the outside of the track are broader than those at the track center, and so the resolution of narrow-track heads decreases.