( 00 l ) epitaxial Ag(Ta0.5Nb0.5)O3 thin films on (001)SrRuO3∕(001)LaAlO3 substrates by chemical solution deposition

Abstract

Epitaxial silver tantalate niobate, Ag(Ta0.5Nb0.5)O3 (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°C in O2 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 100kHz with an increase in the crystallization temperatures from 500to800°C. It is speculated that the phase transition between the orthorhombic M2 and M3 phases (which occurs at ∼330K in ceramics) is shifted to lower temperatures (⩽99K) for the films. For a film that was crystallized at 750°C, the frequency dependence was small (⩽20.3%) within the range of 1Hz–100kHz, the capacitance change, ΔC∕C, 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 100kHz, and the dc field tunability was not hysteretic, but was limited to 4.8% with a 150kV∕cm bias.