Superconducting current in hybrid heterojunctions of metal-oxide superconductors: Size and frequency dependences |
| |
Authors: | Yu V Kislinskii P V Komissinski K Y Constantinian G A Ovsyannikov T Yu Karminskaya I I Soloviev V K Kornev |
| |
Institution: | 1.Institute of Radio-Engineering and Electronics,Russian Academy of Sciences,Moscow,Russia;2.Chalmers University of Technology,G?teborg,Sweden;3.Moscow State University,Moscow,Russia |
| |
Abstract: | We have detected experimentally considerable deviations of the frequency dependences of the Shapiro step amplitudes and the critical current of Nb/Au/YBa2Cu3Ox thin-film hybrid Josephson heterojunctions prepared on YBa2Cu3Ox metal-oxide superconductor films with a tilted c axis from the regularities inherent in Josephson junctions of traditional superconductors with an s-symmetry of the order parameter. It is shown that possible formation of “splintered” fluxons with a size λs<λJ due to faceting of the interface and formation of a chain of nanosize 0 and π junctions must be taken into account in describing processes in lumped heterojunctions (whose size L is smaller than the Josephson penetration depth λJ determined from the averaged value of the critical current density). For heterojunctions with a size λs < L < λJ, a substantial decrease in the maximal amplitude of the first Shapiro step with increasing voltage (Josephson oscillation frequency) is observed at voltages much smaller than the energy gap in niobium (V « ΔNb/e); this effect is manifested most strongly when the size L is greater than λs. A fractional Shapiro step and a subharmonic detector response have been observed in the current-voltage characteristics of heterojunctions; the dynamic processes responsible for their emergence and indicating the presence of the second harmonic in the current-phase relation are studied. It is shown that the effect of interface faceting on the current-phase relation increases with a heterojunction size L>λs. |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|