EPITAXIAL HETEROSTRUCTURES YBA2CU3O7-DELTA KTAO3 FOR MICROWAVE APPLICATIONS/

Combinations of high T-C superconducting and ferroelectric films may g ive rise to tunable, high-Q microwave components. c-axis oriented YBa2 Cu3O7-delta films were grown by laser ablation on (001) and vicinicall y cut KTaO3 substrates and studied by x-ray diffraction and electron m icroscopy. Competitive superconducting properties were registered. YBa 2Cu3O7-delta/KTaO3/YB2Cu3O7-delta trilayers were deposited on silicon- on-sapphire buffered by CeO2/Y-ZrO2. The dielectric permittivity of KT O3 at 15-100 K decreased considerably when the layer was polarized by a dc voltage. A loss factor tan delta=0.007 was measured at 100 kHz an d T=50-100 K. (C) 1995 American Institute of Physics.