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

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