Field effect in perovskite-type manganite films on high-Tc 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 fabricated and their resistivity perpendicular to the plane were measured. A field effect was observed in which the resistivity decreased for 4 orders with 10 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 considered to be a sign of charge-ordering (CO). Annealing, on the other hand, suppressed the macroscopic resistivity of PCMO films. A field effect at room temperature was also observed.