Phase-sensitive evidence for d-wave pairing symmetry in electron-doped cuprate superconductors

Using a scanning SQUID microscope in a series of tricrystal experiments, definitive phase-sensitive evidence for d-wave pairing symmetry in the electron-doped cuprate superconductors NCCO and PCCO was obtained. As a result, predominantly d-wave superconductivity was established in both optimally electron- and hole-doped high-Tc superconductors. Further, the power-law temperature dependence observed in some λab(T) data supports the conclusion that both NCCO and PCCO are d-wave superconductors.