A magnetoresistive device having a high giant magnetoresistance (GMR) value and a moderate low resistance area product (RA) includes a first magnetic layer, a second magnetic layer, and a current confined path (CCP) spacer layer positioned between the first magnetic layer and the second magnetic layer. The spacer layer includes copper current confined paths extending between the first magnetic layer and the second magnetic layer in a matrix of magnesium oxide. The spacer layer is formed by a mixture copper and magnesium oxide, which is heattreated to form the copper current confined paths within the magnesium oxide matrix.