A current-perpendicular-to-the-plane spin-valve (CPP-SV) magnetoresistive
sensor has an insulating layer with at least one aperture that confines
the flow of sense current through the active region. The apertures are
located closer to the sensing edge of the sensor than to the back edge of
the sensor. The aperture (or apertures) are patterned by e-beam
lithography, which enables the number, size and location of the apertures
to be precisely controlled. The insulating layer may be located inside
the electrically conductive nonmagnetic spacer layer, or outside of the
magnetically active layers of the spin-valve. More than one insulating
layer may be included in the stack to define conductive current paths
where the apertures of the insulating layers overlap. The apertures are
filled with electrically conductive material, typically the same material
as that used for the spacer layer.