DC ELECTRIC-FIELD EFFECT ON THE MICROWAVE PROPERTIES OF YBA2CU3O7 SRTIO3 LAYERED STRUCTURES/

We present a summary of our work on the dc electric field effect on th e microwave properties of YBa2Cu3O7/SrTiO3 (YBCO/STO) layered structur es. We briefly describe the fabrication of these layered structures, t heir structural and electrical properties related to the microwave res ponse, and experimental methods to investigate dc electric field effec ts at microwave frequencies. Analysis of microwave measurements shows that dc electric field modulated changes in both the complex conductiv ity of YBCO layers and the dielectric properties of the STO layers con tribute to the overall device response. At low temperatures (<50 K) an d large electric fields, good samples show linear gate-voltage modulat ion of microwave surface resistance and surface reactance attributable to field induced superconducting hole filling and depletion in the do minant YBCO layer.