Electrical characterization of BaTiO3 heteroepitaxial thin films by hydrothermal synthesis

The electrical properties of hydrothermally grown epitaxial pseudocubic BaTiO3 thin films formed on epitaxial electrode layers of SrRuO3 on SrTiO3 single crystal substrates have been evaluated by variable frequency dielectric testing. The initial as-synthesized BaTiO3 film displayed a dielectric constant of 450 with very high losses (tan delta similar to 100%) at 10 kHz due to OH- and H2O, incorporated during growth, contributing to migration losses within the film. Improvements were seen with increasing postprocessing heat-treatment time and temperature with improved properties seen after a heat treatment at 300 degrees C for 24 h (epsilon similar to 200, tan delta similar to 8%). Relationships were established for dielectric constant and loss tangent with structural changes observed by Fourier transform infrared spectroscopy, thermal gravimetric analysis, nuclear magnetic resonance spectroscopy, and x-ray diffraction.