We probe directly the superconducting current-phase relations (CPR) of Nb/Au/(001) YBa2Cu3Ox heterojunctions prepared in epitaxial c-axis oriented YBa2Cu3Ox (YBCO) thin films. The measurements are performed by a single-junction interference experiment. Atomic Force Microscope observations and estimations made from I-V characteristics confirm the c-axis current transport. No deviation of the current-phase relation from a sinusoidal shape has been found within the experimental accuracy. Possible reasons of the absence of the second harmonic in the CPR due to a second order tunneling are discussed.
@article{arxiv.cond-mat/0008077,
title = {Superconducting current-phase relation in Nb/Au/(001)YBa2Cu3Ox heterojunctions},
author = {P. V. Komissinski and E. Il'ichev and G. A. Ovsyannikov and S. A. Kovtonyuk and M. Grajcar and Z. Ivanov and Y . Tanaka and N. Yoshida and S. Kashiwaya},
journal= {arXiv preprint arXiv:cond-mat/0008077},
year = {2007}
}