Studies of transition noise in media recorded by heads with trailing shields

Transition noise and jitter of perpendicular media are improved by writing with pole heads which have trailing shields. This phenomenon may be studied by using forward and backward flying longitudinal ring heads. The forward-flying ring heads write from the trailing edge of the write pole; the reverse-flying ring heads write from the trailing edge of a pole which is followed by a gap and a trailing shield, thus emulating the behavior of a pole head with a trailing shield. This technique allows the evaluation of media signal/noise improvements (2-3 dB) obtained by increasing the write field gradient, the write field angle and hence also the Stoner-Wohlfarth effective write field.