Electric field effects on transport properties in YBa2Cu3O7−δ

Abstract We made field effect transistor-like junctions of YBa 2 Cu 3 O 7−δ (YBCO). Thin YBCO films with 6 and 2 unit cell thicknesses are prepared on a (100) surface of SrTiO 3 . Insulating layer of BaTiO 3 was made on top of YBCO. The application of a negative gate voltage V gate lowers the resistance R linearly in V gate , with a positive V gate having the opposite effect. Near the onset temperature T c 0 of superconductivity, Δ R/R is independent of temperature across T c 0 . This result indicates a small electric field effect on T c 0 for YBCO with high T c 0 (∼ 80 K ).