A differential read head comprises one tri-layer reader or a plurality of tri-layer
readers operating in a current perpendicular to plane (CPP) mode. The tri-layer
readers each comprise a first free layer, a second free layer, and a nonmagnetic
layer positioned therebetween. A nonmagnetic spacer is positioned between the plurality
of tri-layer readers for electrically connecting the plurality of tri-layer readers
in series such that a single CPP sense current representing a differential signal
flows serially through the read head. With a single tri-layer reader, the free
layers are spaced by a width substantially similar to the transition width of the
magnetic medium.