Stoichiometry and superconductivity in the Ln2−xCexCuO4−δ system

Abstract We present a systematic study of the stoichiometry effects on some of the normal state and superconducting properties of Nd 2−x Ce x CuO 4−δ ceramics prepared under various conditions (temperature, oxygen pressure, processing time and cooling rate). We will show that superconductivity can be induced in this system without reduction at low oxygen pressure. We will also present conclusive evidence that Nd 2−x Ce x CuO 4−δ is not a thermodynamically stable phase under the typical synthesis conditions.