PZT films < 700Å have been synthesized by in-situ ion beam sputter deposition on Pt/Ti/MgO and RuO2/SiO2/Si substrates using deposition temperatures ≤ 500°C. Films on Pt/Ti/MgO had a highly preferred (001) orientation, whereas, the films on RuO2/SiO2/Si were randomly oriented. The formation of perovskite vs. pyrochlore phases has been studied. In the case of heavily Sn doped samples, it appeared that the doping promoted the nucleation of pyrochlore. We believe this effect was caused by a substantial reduction in the A:B cation ratio which was the result of Sn contaminated Pb targets. Electrical characterization was performed using parallel-plate electrodes. Hysteresis measurements showed high polarization values and coercive fields for the highly oriented films, whereas, the randomly oriented films showed much lower values of polarization. Fatigue measurements on the highly oriented films showed a sharp drop in polarization at 105 or 106 cycles. A decrease in Pr with time has been observed and is discussed.