Dielectric relaxation and conduction in SrTiO3 thin films under dc bias

The dielectric and conduction behavior of SrTiO3 thin films deposited on a SrTiO3 single-crystal substrate is studied. Without dc bias, an obvious die lectric "defect mode" in the dielectric loss is observed in the temperature range of similar to 100-200 K; however, no noticeable corresponding dielec tric constant peak is observed. By applying a high dc bias (greater than or equal to 40 kV/cm), a dielectric constant peak with frequency dispersion a ppears in the same temperature range, the dielectric loss is increased, and simultaneously high dc conduction is observed. The induced dielectric cons tant peak is related to dc conduction and attributed to the coupling effect of the mobile carriers with the dielectric defect mode. (C) 2001 American Institute of Physics.