Pulse distortion in transitions recorded with thin film pole tips

The transitions recorded on particulate, longitudinal media by a thin film ring head can exhibit a distortion at high write currents that adds an oscillatory structure to the density response and also degrades the amplitude at high density. The main data transition is recorded at the trailing edge of the gap, while the distortion is a second pulse written at the edges of the data track by the trailing edge of the trailing pole tip and at the expense of the transition recorded by the gap. This produces two pulses of opposite polarity with a constant peak-to-peak amplitude, separated by a distance equal to the thickness of the trailing pole tip and with the distortion appearing as a spurious pulse ahead of the data pulse.