Probing the order parameter of magnetically grain-aligned NCCO electron-doped cuprate

Abstract The c -axis alignment of Nd 1.85 Ce 0.15 CuO 4.105 superconducting powder was achieved by applying an external magnetic field of 1 T perpendicular to the axis of rotation of powder/epoxy tetragonal holder. The temperature dependencies of the in-plane penetration depth λ ab and out-of-plane penetration depth λ c were obtained by measuring the zero-filed-cooled ac diamagnetic susceptibility χ d ( T ) in a low applied field ( B a  = 10 Oe). An observed Nd paramagnetic background was subtracted. The relative change temperature dependence penetration depth Δ λ ( T ) =  λ ( T ) −  λ (0) for both c -axis parallel and perpendicular to the applied field can be fitted to a quadratic d-wave rather than an exponential s-wave like function up to 0.5 T c . This result is in agreement with recent experiments suggest the unconventional nature for electron-doped RCCO (R = Pr, Nd, La, Eu, Sm) cuprates.