(001) epitaxial Ag(Ta0.5Nb0.5)O-3 thin films on (001)SrRuO3/(001)LaAlO3 substrates by chemical solution deposition

Abstract

Epitaxial silver tantalate niobate, Ag(Ta0.5Nb0.5)O-3 (ATN), thin films on (001)SrRuO3/(001)LaAlO3 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 degrees C in O-2 ambient. X-ray diffraction data demonstrated cube-on-cube epitaxy, with a limited reaction between the ATN thin films and the SrRuO3. 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 degrees C. It is speculated that the phase transition between the orthorhombic M-2 and M-3 phases (which occurs at similar to 330 K in ceramics) is shifted to lower temperatures (<= 99 K) for the films. For a film that was crystallized at 750 degrees C, the frequency dependence was small (<= 20.3%) within the range of 1 Hz-100 kHz, the capacitance change, Delta C/C, was small (<= 12.1%) over the temperature range of -20-120 degrees C with a corresponding temperature coefficient of capacitance of -0.11%/degrees C at room temperature at 100 kHz, and the dc field tunability was not hysteretic, but was limited to 4.8% with a 150 kV/cm bias. (c) 2007 American Institute of Physics.