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 dielectric ‘‘defect mode’’ in the dielectric loss is observed in the temperature range of ;100–200 K; however, no noticeable corresponding dielectric constant peak is observed. By applying a high dc bias ~>40 kV/cm!, a dielectric constant peak with frequency dispersion appears in the same temperature range, the dielectric loss is increased, and simultaneously high dc conduction is observed. The induced dielectric constant peak is related to dc conduction and attributed to the coupling effect of the mobile carriers with the dielectric defect mode. © 2001 American Institute of Physics. @DOI: 10.1063/1.1389771#