Fabrication of (K,Na)NbO3 films on SrRuO3/(001)SrTiO3 substrates by pulsed laser deposition

Abstract

1–3-µm-thick (K,Na)NbO3 films were epitaxially grown on SrRuO3/(001)SrTiO3 substrates by the pulsed laser deposition using (KxNa1−x)NbO3 targets. Energy dispersive X-ray spectroscopy analysis showed that the film K content was about 10% lower than the target K content x at x = 0.1–0.8, and the (K + Na)/Nb atomic ratio was 0.8–1.0. Reciprocal space mapping of the films revealed that the films were epitaxially grown at x = 0–0.7, and the crystal system was altered with increasing K content. Ferroelectric polarization–electric field loops were observed at x = 0–0.9, with the maximum remanent polarization of ∼40 µC/cm2 at x = 0.5. The remanent polarization vs K content profile was discussed with crystal structure analyses.