Measurements of lattice-matched antiferromagnetic/ferromagnetic films which are ideal layered systems to study exchange bias are reported. Epitaxial films of FePt3 have two kinds of antiferromagnetic ordering. The spin ordering phase with wave vector Q/1 = (1/2 1/2 0) has a Neel temperature T-N = 160 K and that with wave vector Q(2) = (1/2 0 0) has T-N = 100 K. Neutron diffraction confirmed the presence of Q(2) = (1/2 0 0) antiferromagnetic ordering in 200 nm Fe25Pt75 grown on MgO(100). The loop shift and coercivity of a trilayer film of CoPt3/FePt3/CoPt3 decrease with increasing temperature, consistent with the observed Neel temperature of FePt3. The x-ray diffraction rocking curve widths of films grown on MgO(100) and Al2O3(11 (2) under bar0) are compared and related to the loop shifts that are observed in the films with lattice-matched antiferromagnetic/ ferromagnetic interfaces. (C) 2006 American Institute of Physics.