Fabrication and characterization of ferroelectric PLZT film capacitors on metallic substrates

We have grown ferroelectric Pb_0.92La_0.08Zr_0.52Ti_0.48O₃ (PLZT) films on Hastelloy C276 (HC) substrates by chemical solution deposition. Samples of 1.15-μm-thick PLZT films were prepared on HC with and without lanthanum nickel oxide (LNO) films as an intermediate buffer layer. On samples with and without LNO buffers at room temperature, we measured dielectric constants of ≈1,300 and ≈450 and loss tangents of ≈0.06 and ≈0.07, respectively. For PLZT films grown on HC with LNO buffer, the dielectric constant increases, while the dielectric loss decreases, with increasing temperature. A dielectric constant of ≈2,000 and loss of ≈0.05 were observed at 150 °C. Samples with LNO buffer also exhibited slimmer hysteresis loops and lower leakage current density when compared to samples without LNO buffer. The following results were measured on samples with and without LNO buffers: remanent polarization (P_r) values of 21.3 and 36.4 μC/cm², coercive electric field (E_c) values of 41 and 173 kV/cm, and leakage current densities of ≈1.1 × 10⁻⁸ and ≈1.6 × 10⁻⁷ A/cm², respectively. The energy storage capability was measured at ≈65 J/cm³ for the PLZT film-on-foil capacitor deposited on HC with LNO buffer.