Relaxor behavior and energy storage performance of ferroelectric PLZT thin films with different Zr/Ti ratios

Ferroelectric lead lanthanum zirconate titanate (PLZT) films with 8 mol% lanthanum and different Zr/Ti ratios (70/30, 65/35, 58/42, 52/48, 45/55, and 40/60) have been grown on platinized silicon substrates by chemical solution deposition. The effects of the Zr/Ti ratios on the dielectric and ferroelectric properties were investigated for high-power energy storage applications. These films exhibited relaxor behavior and slim polarization–electric field hysteresis loops, and the degree of phase transition diffuseness decreased with increasing Ti. The PLZT films with Zr/Ti=52/48 had a high spontaneous polarization of ≈51.2 μC/cm2, a low remanent polarization of ≈9.1 μC/cm2, and a low coercive electric field of ≈25.9 kV/cm, leading to a recoverable energy density of ≈30 J/cm3 and a charge–discharge efficiency of ≈78% at room temperature. The high energy density and high efficiency indicate that relaxor PLZT with La/Zr/Ti=8/52/48 is a promising candidate for high-power film capacitors.