D-Wave Superconductivity Develops Out Of The Fermi Liquid Ground State In Electron-Doped Superconductor Pr0.91ce0.09lacuo4-Y

NMR measurements on n-type copper-oxide Pr0.91Ce0.09LaCuO4-y (T-c = 24 K) are reported. The results of the spin-lattice relaxation rate and the Knight shift indicate that the superconducting gap possesses line nodes, consistent with d-wave symmetry. We further find that no pseudogap appears in the normal state even though the present sample is low-doped. The latter property contrasts with that in p-type copper-oxides with similar doping level where superconductivity sets in a pseudogap state. (C) 2004 Published by Elsevier B.V.