A magnetoresistive (MR) sensor for MR heads comprising a magnetoresistive ferromagnetic layer (MR layer) and an antiferromagnetic layer in direct contact with the surface of the MR layer. The MR layer has a face-centered-cubic (fcc) structure. The crystalline structure of the antiferromagnetic layer is the fcc structure in the vicinity of the interface of the MR layer and the antiferromagnetic layer, and continuously changes to a face-centered-tetragonal (fct) structure toward the surface opposite to the interface. The interface of the MR layer and the antiferromagnetic layer is continuous with respect to the crystalline structure due to the epitaxial growth of the antiferromagnetic layer on the surface of the MR layer.