Fatigue, retention and switching properties of PLZT(x/30/70) thin films with various La concentrations

We investigated the fatigue, retention and switching properties of PLZT(x/30/70) thin films with various La concentrations. By applying 10⁹ square pulse switching cycles with a voltage of ±5 V to study the fatigue properties of the film, we found that the decrease of the initial polarization is improved from 64% to 40% as the La concentration is increased from 0 mol% to 10 mol%. The retention properties are also greatly improved as the decrease of the initial polarization decrease is reduced from 47% to 9% after 10⁵ s. The switching time is decreased from 0.8 μs to 0.55 μs as the La concentration is increased. While the dielectric constant of the PLZT thin films increases from 450 to 600 as the La concentration is increased, the dielectric loss and leakage current density measured at 100 kV/cm decrease from 0.075 to 0.025 and from 5.83 × 10⁻⁷ to 1.38 × 10⁻⁷ A/cm², respectively. By analyzing the hysteresis loops of the PLZT thin film measured at 175 kV/cm, we found that the remnant polarization and coercive electric field decrease from 20.8 μC/cm² to 10.5 μC/cm² and from 54.48 kV/cm to 32.12 kV/cm, respectively, as the La concentration is increased.