A method and apparatus for increasing the electrical resistivity and corrosion resistance of the material forming a spacer layer in current-perpendicular-to-the-plane (CPP) giant magnetoresistive (GMR) sensors. The increased resistivity of the spacer layer, and thus, the CPP-GMR sensor permits a larger voltage across the sensor and a higher signal-to-noise ratio. The increased corrosion resistance of the spacer layer minimizes the effects of exposing the spacer layer to corrosive materials during fabrication. For example, adding tin to silver to form a metallic alloy spacer layer increases the corrosion resistance of the spacer layer and the electrical resisitivity of the CPP-GMR sensor relative to a spacer layer consisting solely of silver. The Ag—Sn alloy permits a larger current to flow through the sensor, which increases the signal-to-noise ratio.