An amorphous phase was formed in a 0.95(Na0.5K0.5)NbO3-0.05CaTiO3 (NKN-CT) film grown at 300°C, and a low-temperature transient Ca2Nb2O7 phase was formed in the film grown at 500°C. In films grown at high temperatures (≥600°C), secondary phases such as K5.75Nb10.85O30 and K4Ti10Nb2O27 were developed without the formation of a NKN-CT phase, probably because of Na2O evaporation. The same secondary phases were formed in the film grown at 300°C and subsequently annealed at 850°C under an air atmosphere. However, a homogeneous NKN-CT phase was formed in films grown at 300°C and subsequently annealed at 830°C-880°C under the K2O and Na2O atmospheres. Moreover, the film annealed at 830°C in particular exhibited good electric and piezoelectric properties, including a high dielectric constant of 747 with a low dissipation factor of 0.93% at 100 kHz, low leakage current density of 2.0 × 10-7 A/cm2 at 0.1 MV/cm, and high Pr and d33 values of 15.4 μC/cm2 and 124 pm/V at 100 kV/cm, respectively.
Bibliographical notePublisher Copyright:
© 2014 The American Ceramic Society.
ASJC Scopus subject areas
- Ceramics and Composites
- Materials Chemistry