Abstract
New explanation is given concerning phase separation i.e., consequences of Cu(1−y) deficiency, generally observed in samples of nominal stoichiometry RE2−xCexCuO4 (RE=lanthanide), reported to happen in T′ structure phases during synthesis in air above 1000°C. Contrary to some literature data, it is assumed herein that phase separation mentioned takes place not during reductive annealing but already during synthesis in air. Accompanying evaporation of Cu, this process leads to RE-site deficient T′ skeleton(s). Based on literature available phase equilibria in Nd2O3–CeO2–CuO system, plausible structure deficiencies are presented and discussed. It is shown that reductive annealing of so defected T′ matrices leads to removal of only tiny amounts of oxygen, the latter resulting from higher than +2 Cu valence and from Cu deficiency factor (1−y). As confirmed on Nd1.95−xCexCuO4 sample (x=0.15), doping of Cu ions with electrons appears not to be a crucial factor for appearance of superconductivity in T′ phase.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
