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Superconductor-ferroelectric-superconductor (SFS) structures were produced by magnetron sputtering of ceramic YBa2Cu307-s and BaxSrr-,Ti03 targets. Raman spectroscopy was effectively used for characterization of superconducting and ferroelectric films in layered structures. Electrical characteristics, such as the temperature dependence of resistance, currentvoltage and capacitance-voltage characteristics were measured. The possibility of applying SFS structures as cwoelectronic caDacitors with voltage control is demonstrated.

The structure and crystallographic mientation d Y B ~& U ~O , -~ films on B;tiSr,-xTi03/Mg0 heteroepitaxial layers were investigated by the conventional methods of electron diffraction, electron microscopy and by specific methods of Raman scattering of light and backscattering ci middle-energy ions. A film of over 350 nm thick may consist of an inner highly-oriented layer and an outer disoriented one. Measurements of the microwave surface resistance R, at 60 GHz and 4.2 K have confirmed a complicated character of the film structure. It has been shown that the microwave response of twc-layer films in a static magnetic field is determined by the losses in the cuter disoriented or granular layer and that the dependence R,(H-) appears in the field H-starting from approximately 10 Oe. In highly-oriented films no dependence of R, on the magnetic field H-was observed in the range from 0 to 100 Oe.