Top-interface-controlled fatigue of epitaxial Pb(Zr0.52Ti0.48)O3 ferroelectric thin films on La0.7Sr0.3MnO3 electrodes

Abstract

Epitaxial Pb(Zr0.52Ti0.48)O3/La0.7Sr 0.3MnO3(PZT/LSMO) and LSMO/PZT/LSMO heterostructures have been grown on LaAlO3(001) substrates by pulsed-laser deposition. Three types of ferroelectric capacitors, i.e., Pt/PZT/LSMO (A), LSMO/PZT/LSMO (B), and Pt/PZT/LSMO |(C) have been fabricated, where the Pt electrode was sputter deposited onto as-grown (capacitor A) and in situ annealed (capacitor C) PZT/LSMO films, respectively. It is found that the LSMO/PZT/LSMO capacitor shows a low coercive field and good fatigue endurance up to 1010 switching cycles. Similar properties are also obtained for capacitor A. However, the capacitor C. with the PZT film in situ annealed at reduced oxygen pressures, exhibits higher switching voltages and starts to fatigue rapidly at about 106 bipolar switching cycles. Lead deficiency at the surface of the annealed PZT films has been observed. Our results demonstrate that the fatigue performance of PZT/LSMO films, although affected greatly by the electrode configurations, is intrinsically determined by the interface property at the top electrode.