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(s )t product of the perpendicular medium; D-50 is comparable. The step f unction pulse is confirmed in this experiment too, which is well expla ined by the reciprocity theorem using numerically calculated head sens itivity function. Differentiation of the signal brings familiar single peak pulses, and improves D-50 by about 30%. Signal reproduction from a narrow track of 0.5 mu m width is demonstrated with a MR head. Writ ing head comparison between a thin film ring head and a single pole he ad is also discussed for the perpendicular double layered medium.