A current-perpendicular-to-the-plane giant magnetoresistance (CPP-GMR) sensor has a multilayer reference layer containing a Heusler alloy. The multilayer reference layer may be a simple pinned layer or the AP2 layer of an antiparallel (AP)-pinned structure. The multilayer reference layer is formed of a crystalline non-Heusler alloy ferromagnetic layer on either an antiferromagnetic layer (in a simple pinned structure) or an antiparallel coupling (APC) layer (in an AP-pinned structure), a Heusler alloy layer adjacent the sensor's nonmagnetic electrically conducting spacer layer, and an intermediate substantially non-crystalline X-containing layer between the crystalline non-Heusler alloy layer and the Heusler alloy layer. The element X is selected from one or more of tantalum (Ta), hafnium (Hf), niobium (Nb) and boron (B).