Growth of Epitaxial 100-Oriented KNbO 3 –NaNbO 3 Solid Solution Films on (100) c SrRuO 3 ∥(100)SrTiO 3 by Hydrothermal Method and Their Characterization

Films of solid solution in KNbO 3 –NaNbO 3 (KNN) were deposited at 240 °C on (100) c SrRuO 3 ∥(100)SrTiO 3 substrates by the hydrothermal method. (K x Na 1- x )NbO 3 films with x = 0–1.0 were synthesized by changing the fraction of KOH in a solution of KOH and NaOH. The x in (K x Na 1- x )NbO 3 continuously changed with the volume fraction of KOH, while the deposition amount strongly depended on x . Epitaxial films with 100 orientation were obtained in the entire composition range and their out-of-plane lattice spacing changed with x . All the films showed ferroelectricity and their remanent polarization became larger than what above x = 0.58.