Radio-frequency electromagnetic field influence on critical behavior of thin granular Y-Ba-Cu-O films.

A dc critical current response of a thin (300nm) c-oriented granular Y-Ba-C u-O film to an excitation of radiofrequency (up to 10MHz) electromagnetic f ield has been studied at the temperature 77K. We have used the scheme where a bridge of the film is radiated by an overhead coil loading radiofrequenc y (RF) generator. The dependencies of the critical current value vs the amp litude and the frequency of the RF field have been obtained. For the each d iscrete frequency in the range of 0 to 10MHz the critical current becomes z ero at some threshold value of the RF field amplitude. The critical current suppression maximum factor has been obtained at the frequency 10MHz which was equal to 5. The results could serve as a basis for treating three-termi nal superconducting devices.