Observation of the second harmonic in superconducting current-phase relation of Nb/Au/(001)YBa<sub>2</sub>Cu<sub>3</sub>O<sub>x</sub> heterojunctions
P. V. Komissinski; E. Il'ichev; G. A. Ovsyannikov; S. A. Kovtonyuk; M. Grajcar; R. Hlubina; Z. Ivanov; Y. Tanaka; N. Yoshida; S. Kashiwaya
Журнал:
EPL (Europhysics Letters)
Дата:
2002-02-01
Аннотация:
The superconducting current-phase relation (CPR) of Nb/Au/(001)YBa<sub>2</sub>Cu<sub>3</sub>O<sub>x</sub> heterojunctions prepared on epitaxial c-axis–oriented YBa<sub>2</sub>Cu<sub>3</sub>O<sub>x</sub> thin films has been measured in a single-junction interferometer. For the first time, the second harmonic of the CPR of such junctions has been observed. The appearance of the second harmonic and the relative sign of the first and second harmonics of the CPR can be explained assuming that the macroscopic pairing symmetry of our YBa<sub>2</sub>Cu<sub>3</sub>O<sub>x</sub> thin films is of the d + s type.
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