Preparation of ferroelectric NaNbO 3/thin films on MgO substrate by pulsed laser deposition

We successfully fabricated good quality NaNbO₃ (NN) films on MgO substrate by pulsed laser deposition using a K-Ta-O (KTO) buffer layer. An SrRuO₃ (SRO) lower electrode layer was deposited on a KTO buffer layer/(100)MgO substrate and then the NN film was deposited on top. X-ray diffraction showed that the SRO and NN films were epitaxially grown on (100)MgO substrate. Transmission electron microscopy showed a crystal- lographic relationship of [001]_NN//[001]_MgO between NN and MgO. The relative dielectric constant, epsiv_r, and dielectric loss, tan delta, of the film were 350 and 0.05 at 1 kHz, respectively. The polarization vs. electric field (P-E) hysteresis loop of the NN film was characteristic of ferroelectric behavior.