Measurements of side writing on a large-scale recording model

The magnetic charge density existing in a recording medium containing an isolated transition has been mapped experimentally in the region of the track edge using a large scale, magnetic model of a head and medium. This was accomplished by measuring the perpendicular field component emanating from the medium at its surface. The gap field of the head and the pole tip offset at the track edge were varied to study their influence on side writing. The results show clearly that the locus of the transition is doubly curved in the side writing zone and that the curvature and lateral extent of the transition increase with gap field and pole tip offset. The measured medium field maps are also compared to calculations of the write head fields in the side writing zones, and the correlation of features in the experimental data with the contour plots of the write field components is discussed.