Field effect in perovskite-type manganite films on high-T-c superconductor

Layered-type junctions of perovskite-type manganite Pr1-xCaxMnO3-y (PCMO; x = 0.3, 0.4, 0.5) and high-Tc superconductor YBa2Cu3O7-z(YBCO) were fabrica ted and their resistivity perpendicular to the plane were measured. A field effect was observed in which the resistivity decreased for 4 orders with 1 0 V of applied voltage at 30 K. Several oxygen-annealed junctions showed an abrupt drop of resistivity at about 2 V, independently to x, which is cons idered to be a sign of charge-ordering (CO). Annealing, on the other hand, suppressed the macroscopic resistivity of PCMO films. A field effect at roo m temperature was also observed.