Phase transitions and electrical behavior of lead-free (K0.50 Na0.50) NbO3 thin film

Abstract

Lead-free (K0.50 Na0.50) NbO3 (KNN) thin films with a high degree of (100) preferred orientation were deposited on the SrRuO3 -buffered SrTiO3 (100) substrate by off-axis radio frequency magnetron sputtering. They possess lower phase transition temperatures (To-t ∼120 °C and Tc ∼310 °C), as compared to those of KNN bulk ceramic (To-t ∼190 °C and Tc ∼400 °C). They also demonstrate enhanced ferroelectric behavior (e.g., 2 Pr =24.1 μc/cm2) and fatigue endurance, together with a lower dielectric loss (tan δ∼0.017) and a lower leakage current, as compared to the bulk ceramic counterpart. Oxygen vacancies are shown to be involved in the conduction of the KNN thin film. © 2009 American Institute of Physics.