Experimental Study of Perpendicular Write Head Field Rise Time

In this paper, a simple technique that can determine the write head field rise time based on electrical measurements is presented. A model that relates the head electrical properties to the frequency dependent head efficiency epsiv(omega) and head field rise time tau is described in detail. This method only requires knowledge of the complex impedances of a magnetically saturated head and an unsaturated head. The results obtained are verified with recording measurements of the rise time for the same heads. Very good agreement was found for all heads. It was also found that the presence of a soft underlayer does not seem to significantly affect the measured head field rise time. Therefore, it is concluded that the head field rise time is determined by the yoke structure and not by the pole tip area