Dielectric properties of epitaxial BaTiO3 thin films

The dielectric response of epitaxial BaTiO3 thin films deposited on MgO was measured through surface electrodes as a function of applied bias, frequency, and temperature. The room temperature value of the dielectric constant was similar to 500 with a dissipation factor, tan(delta), of 0.05 at 100 kHz. Measurements varying the bias field showed hysteresis of the dielectric response and a tunability of 30% for a maximum applied field of similar to 7 MV/m. The frequency response of the dielectric constant is well described by a Curie-von Schweidler power law with an exponent similar to 0.04 in the range 1 kHz-13 MHz. The films undergo a diffuse phase transition at temperatures higher than the bulk Curie temperature. The behavior of the dielectric response is attributed to the presence of residual strain in the epitaxial thin films. (C) 1998 American Institute of Physics. [S0003-6951(98)00642-1].