... 73, No. 7, 2001, pp. ... Observation of the Second Harmonic in the Phase Dependence of a Superconducting Current in Nb/Au/ YBCO Heterojunctions P. V. Komissinskioe1,2, G. A. Ovsyannikov1, E. Il'ichev3, and Z. Ivanov2 Institute of Radio Engineering and Electronics ... Institute for Physical High Technology, Department of Cryoelectronics, P.O. Box 100239, D-07702 Jena, Germany Received February 21, 2001 ; in final form, March 12, 2001 1 3 The second harmonic in the dependence of a ...