A spin valve sensor is provided with a biasing layer which produces a demagnetizing field which supports a demagnetizing field from a pinned layer structure in counterbalancing a sense current field on the free layer structure. The biasing layer has a high resistance so that a sense current is not excessively shunted therethrough and is a specular reflector so as to reflect conduction electrons to increase a magnetoresistive coefficient dr/R of the sensor. In the preferred embodiment the pinned layer structure is an antiparallel (AP) pinned layer structure.