A Josephson supercurrent, which can be split by microwave photons of frequency v into Shapiro steps of spacing TRIAN OP V equals hv/2e, is expected between superconductors of like pairing type, either s- or p-wave. A weaker, and possibly unobservable effect, with step spacing TRIAN OP V/2 was predicted by Pals and van Haeringen between electrodes of unlike pairing type. Experiments using K-band microwaves and a Nb point contact have been carried out at 1. 2 K on the d-band superconductors LiTi//2O//4 and Lu//2Fe//3Si//5. In both cases we find unambiguous indication of s-wave pairing, as in Nb. The same experiment on the heavy-fermion superconductor UBe//1//3 in the range 0. 7-7 K also reveals steps of spacing TRIAN OP V. This indicates that UBe//1//3 has been induced into a state of s-wave superconductivity by proximity with the s-wave superconductor Nb.
|Original language||English (US)|
|Number of pages||4|
|State||Published - Jan 1 1985|
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