Phase-sensitive order parameter symmetry test experiments utilizing Nd2-xCexCuO4-y/Nb zigzag junctions

Phase-sensitive order parameter symmetry test experiments are presented on the electron-doped high-T_c cuprate Nd2-xCexCuO4-y. These experiments have been conducted using zigzag-shaped thin film Josephson structures, in which the Nd2-xCexCuO4-y is connected to the low-T_c superconductor Nb via a Au barrier layer. For the optimally doped as well as for the overdoped Nd2-xCexCuO4-y a clear predominant dx2-y2-wave behavior is observed at T=4.2K. Both compounds were also investigated at T=1.6K, presenting no indications for a change to a predominant s-wave symmetry with decreasing temperature.