ELECTRIC-FIELD EFFECT DEVICES MADE OF YBA2CU3O7-X SRTIO3 EPITAXIAL MULTILAYERS/

Three terminal superconducting electric-field effect devices, consisti ng of a bufferlayer of PrBa2Cu3O7-x, an ultrathin layer of YBa2Cu3O7-x and a SrTiO3 gate isolation layer were fabricated and successfully op erated. Transmission electron microscopy and laser scanning microscopy showed that all layers are highly epitaxial and uniform over the devi ce area. This is essentially important in the analysis of the mechanis m of the electric field effect and for the reproducible fabrication of devices. With a 5 nm thick YBa2Cu3O7-x layer and an applied electric field of 0.85 MV/cm the critical current was decreased by 5% at low te mperatures and up to 36% close to T(c). Also enhancement was obtained.