Large dielectric constant arising from space‐charge polarization in a SrTiO3 thin film grown on an YBa2Cu3O7–δ layer

Abstract

AbstractThe frequency and temperature dependence of the dielectric constant of SrTiO3 (STO) thin‐film capacitors in multilayer structures of YBa2Cu3O7–δ/SrTiO3/YBa2Cu3O7–δ films were measured over the frequency range 100 to 106 Hz at 2–300 K. In a 750‐nm‐thick STO film, a low‐frequency dielectric dispersion gradually occurs in the temperature region below 50 K; at 5 K, the dielectric constant εr increases to 1.1 × 105 at frequencies below 103 Hz. A space‐charge polarization mechanism is responsible for the large observed dielectric constant of the STO thin films at low temperatures. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)