Preparation of PZT thin films on YBCO electrodes by KrF excimer laser ablation technique

Pb(Zr_xTi_1-x)O₃ (PZT) films have excellent ferroelectric, optical, piezoelectric, and pyroelectric properties. We prepared PZT thin films by the excimer laser ablation technique. A pulsed KrF excimer laser (Lambda Physik LPX305icc, pulse duration of 25 ns, λ = 248 nm, 850 mJ Max.) was used to ablate the bulk targets. We investigated the influence of bottom electrode materials on the characteristics of the PZT thin films prepared on Pt and YBCO underlayers. The X-ray diffraction (XRD) patterns showed that the PZT films prepared with a laser fluence of 2 J cm^-2 on YBCO/MgO(100) substrate at a wide temperature range of 550-680 °C have a perovskite (00l) structure. At the same laser fluence, the PZT films prepared on Pt/MgO(100) substrate have a perovskite (00l) structure only at 650 °C . The polarization-electric field (P-E) characteristics and fatigue properties of PZT thin films were measured by the Sawyer-Tower circuit. The remnant polarization and coercive field have been found to be P_r =15 μCcm^-2, 30 μC cm^-2 and E_c = 200 kV cm^-1, 100 kV cm^-1 for Au/PZT/Pt/MgO and Au/PZT/YBCO/MgO correspondingly. The remnant polarization of Au/PZT/YBCO/MgO thin film was reduced to one-half after about 10⁸ cycles of switching.