Low temperature synthesis and electrical properties of epitaxial Sr0.8Bi2.2Ta2O9 thin films

High quality epitaxial thin films of Sr0.8Bi2.2Ta2O9 (SBT) were grown on La NiO3 (LNO) bottom electrodes. The SBT/LNO heterostructure was fabricated on (001) oriented LaAlO3 substrates by pulsed laser ablation. X-ray diffracti on and high resolution transmission electron microscopy revealed epitaxial growth of SBT and LNO layers along the (001) direction and sharp interfaces between the epilayers. The SBT films exhibited a dielectric constant of si milar to 270 and the loss tangent varied from 0.02 to 0.04. The dielectric constant measured as a function of bias field revealed that the films were not ferroelectric in nature. The room temperature frequency response of the dielectric constant was observed to obey Curie-von Schweidler power law wi th an exponent of 0.02 in the range of 10 kHz-1 MHz. (C) 2001 American Inst itute of Physics.