A study of the microcracks on the alumina of the thin-film head

A study of the microcracks found in the alumina of a magnetic thin film head is presented. The initiation and growth of the cracks was simulated. Thermal expansion of the energized wires was found to produce high stress at the pole tip area resulting in the cracks being attracted to the pole tips. Damages on the alumina act as crack initiation sites. The presence of a crack through the head gap also affects the recording performance of the head.