Fig. 1

Probing the CPR with a Josephson interferometer. a SEM image of a JI device. The scale bar is 2 μm. This device consists of two Josephson junctions in parallel and enables probing the CPR of the smaller junction. The Aluminum electrodes are 50 nm thick. b Voltage map as a function of current and magnetic field B_z applied perpendicular to the film plane showing zero voltage below a critical current value. The critical current of the small junction oscillates with the magnetic flux in the superconducting loop. c IV curve of the JI device. The critical current value I_c is extracted when the junction develops a finite voltage defined as B_z and indicated by the dashed vertical line. d Critical current extracted from c as a function of B_z. The oscillations are properly described by the function \(I_{\mathrm{c}}\left( {B_z} \right) = I_{{\mathrm{c}}_{\mathrm{1}}} + I_{{\mathrm{c}}_{\mathrm{2}}}{\mathrm{cas}}(\omega B_z)\), indicating a sinusoidal CPR as expected for conventional Josephson junctions