UNUSUAL PROPERTIES OF ND1.85CE0.15CUO4+ -DELTA WITH VARYING OXYGEN CONCENTRATION/

We have studied in detail the in-plane transport properties of Nd1.85C e0.15CUO4+/-delta (NCCO) films and crystals over a wide range of oxyge n concentration, We find that the appearence of superconductivity stro ngly correlates with a positive magnetoresistance in the normal state as well as a positive component to the negative Hall coefficient. Toge ther with our observation of an anomalously large discrepency between the Hall angle obtained from the Hall effect and resistivity and that obtained from the Nernst and Seebeck effects, our data provide strong evidence for the existence of hole and electron carriers in this ''ele ctron-doped'' superconductor.