(00l) epitaxial Ag (Ta0.5 Nb0.5) O3 thin films on (001) SrRu O3 (001) LaAl O3 substrates by chemical solution deposition

Epitaxial silver tantalate niobate, Ag (Ta0.5 Nb0.5) O3 (ATN), thin films on (001) SrRu O3 (001) LaAl O3 substrates were deposited by a chemical solution deposition route. The solution was prepared using niobium ethoxide, tantalum ethoxide, and silver nitrate precursors in a 2-methoxyethanol and pyridine solvents. Films were crystallized between 450 and 800 °C in O2 ambient. X-ray diffraction data demonstrated cube-on-cube epitaxy, with a limited reaction between the ATN thin films and the SrRu O3. The dielectric constants of the epitaxial films improved from 260 to 360 at 100 kHz with an increase in the crystallization temperatures from 500 to 800 °C. It is speculated that the phase transition between the orthorhombic M2 and M3 phases (which occurs at ∼330 K in ceramics) is shifted to lower temperatures (≤99 K) for the films. For a film that was crystallized at 750 °C, the frequency dependence was small (≤20.3%) within the range of 1 Hz-100 kHz, the capacitance change, ΔCC, was small (≤12.1%) over the temperature range of -20-120 °C with a corresponding temperature coefficient of capacitance of -0.11%°C at room temperature at 100 kHz, and the dc field tunability was not hysteretic, but was limited to 4.8% with a 150 kVcm bias.