Table 1 Summary of the main characteristics of the point-contact Josephson junctions studied in this work. \(I_c\) is the critical current of the contact, \(R_N\) its resistance, determined from the low-voltage part of \(I-V\) curve, \(V_c=I_c R_N\) is the characteristic voltage of the junction, \(I_{non-J}/I_c\) is the percentage of the superconducting non-Josephson current, \(\Omega _{VAC}\) the normalized frequency of the microwave radiation as determined directly from the current-voltage characteristic. \(\eta _1\), \(\Omega _\varphi\) and \(\Omega _{2 \varphi }\), which are shown in Fig. 6, are the normalized oscillation period of the first current step and the normalized frequencies of the microwave radiation, found from the oscillation periods of the first current steps for the two different \(I_s(\varphi )\) relationships, respectively. For contact No. 8 there is no intersection between \(\eta _1\) and \(\Omega _{2 \phi }\).

From: Probing the current-phase relation in Josephson point-contact junctions between \(\hbox {Pb}_{0.6}\)In\(_{0.4}\) and \(\hbox {Ba}_{0.6}\)K\(_{0.4}\)(FeAs)\(_2\) superconductors