Characterization of Ferroelectric Na_xK_1−xNbO₃ System Films Prepared by Pulsed Laser Deposition

Abstract

Ferroelectric Na_xK_1−xNbO₃ (NKN) films were prepared on quartz and Pt/SrTiO₃(100) substrates by pulsed laser deposition. The effects of composition and preparation conditions on the crystal structure and ferroelectricity of the NKN films were investigated by changing the Na content (x), substrate temperature (T_sub), oxygen partial pressure (P_O2), target-to-substrate distance (D_t-s) and laser energy density (E_L). The permittivity values of the NKN films were 390 to 520 at room temperature and 100 kHz, showing a maximum at x=0.5. The maximum remnant polarization value was 8.2×10⁻² C m⁻² at x=0.5.