Structure and dielectric behavior of epitaxially grown SrTiO3 film between YBa2Cu3O7-δ electrodes

To obtain a high insulating SrTiO3 layer, the parallel capacitors of epitaxially grown YBa2Cu3O7-delta/SrTiO3/YBa2Cu3O7-delta have been fabricated by a Chemical Mechanical Planarization method. The dielectric constant and tan delta of the SrTiO3 film at 2.2 K was 27000 and 0.027 at 10 kHz, respectively. The temperature variation of the dielectric constant could be well fitted by the formulae of Curie-Weiss and Barrett in the temperature ranges above 100 K and 30 < T < 100 K, respectively. The best-fit parameters were coincident with those for SrTiO3 single crystals. In order to examine the influence of degraded SrTiO3 layers at the YBa2Cu3O7-delta/SrTiO3 interfaces on the dielectric constant, a multilayer model involving two kind of SrTiO3 layers with different dielectric characteristics was proposed. The results revealed that the degraded SrTiO3 layer is very thin and the dielectric constant of the SrTiO3 film was dominated by that of single-crystal-like SrTiO3 layer.