cpp magnetic read head designs have been improved by increasing the length of the afm layer relative to that of both the free and spacer layers . the length of the pinned layer is also increased , but by a lesser amount , an abutting conductive layer being inserted to fill the remaining space over the afm layer . the extended pinned layer increases the probability of spin interaction while the added conducting layer serves to divert sensor current away from the bottom magnetic shield which now is no longer needed for use as a lead .