Magnetic-field dependence of the maximum supercurrent of La2-xCexCuO4-y interferometers:: Evidence for a predominant dx2-y2 superconducting order parameter -: art. no. 057004

We performed a phase-sensitive test of the symmetry of the superconducting order parameter of the electron doped cuprate La2-xCexCuO4-y using a superconducting quantum interferometer with spatially distributed Josephson junctions. The studies were made on a thin film grown on a SrTiO3 tetracrystal substrate. The superconducting transition temperature was about 29 K which indicates that the sample is close to optimal doping. The magnetic field dependence of the critical current gives strong evidence for a predominant d(x)(2)-y(2) order parameter symmetry of the sample measured. It also gives upper limits for the s-wave component in a mixed order parameter of the type s+id(x)(2)-y(2).