Polycrystalline Pb(Zr0.52Ti0.48)O-3 (PZT) thin films between 250 and 1000 nm thick were deposited on Cu foils via RF magnetron sputtering. Samples were crystallized ex situ between 550 degrees C and 750 degrees C in a low oxygen partial pressure atmosphere, pO(2), in order to avoid oxidation of the substrate. These were compared to films made on more common Pt/TiOx/SiO2/Si substrates also crystallized under low pO(2) conditions. The mismatch of the coefficients of thermal expansion for Cu and PZT caused large compressive residual stresses to develop in the films, whereas films on Pt-Si experienced more moderate tensile stresses. Stress was measured using the sin(2)psi method. In addition to mechanical implications, i.e., film cracking and delamination, the effect of residual stress on electrical properties is discussed. Dielectric constants of PZT were lower on Cu than on Pt/TiOx/SiO2/Si. This could be due either to a dead layer effect or to the residual stress imposed by the substrate. The remanent polarizations for films on Cu were between 18 and 41 mu C/cm(2), while coercive fields were between 37 and 54 kV/cm. Rayleigh analysis was used to describe the role of defects affecting domain wall mobility, as they act as pinning centers and decrease the extrinsic polarization response.