MR head reading characteristics in perpendicular magnetic recording

Reading characteristics of an MR head for perpendicular magnetization are theoretically and experimentally examined. Higher output than with an ordinary longitudinal medium is obtained because of the higher M/sub s/t product of the perpendicular medium; D/sub 50/ is comparable. The step function pulse is confirmed in this experiment too, which is well explained by the reciprocity theorem using numerically calculated head sensitivity function. Differentiation of the signal brings familiar single peak pulses, and improves D/sub 50/ by about 30%. Signal reproduction from a narrow track of 0.5 /spl mu/m width is demonstrated with a MR head. Writing head comparison between a thin film ring head and a single pole head is also discussed for the perpendicular double layered medium.