A2Nb1+XOY (A=Ca, Sr) ( 0\lesssimx\lesssim5): New Reduced Niobate Superconductors with the Distorted Defect-Perovskite Structure
- 1 April 1994
- journal article
- Published by IOP Publishing in Japanese Journal of Applied Physics
- Vol. 33 (4B) , L583
- https://doi.org/10.1143/jjap.33.l583
Abstract
From the DC magnetization and powder X-ray diffraction (XRD) measurements, in the defect-perovskitc-type reduced niobates A2Nb1+ X O Y (A=Ca, Sr), we found at least two kinds of broad superconducting phases with the critical temperatures of about 9.2 K (for 0\lesssimx\lesssim1.0) and 8.3 K (for 1.2–1.5\lesssimx\lesssim5.0) covering almost the whole valence state of Nb from Nb1+ to Nb5+ in the Ca system and in the somewhat narrower range in the Sr system. The highest shielding effect in these phases of both systems is attained for samples prepared from the starting mixtures having the initial mean Nb valence between 1+ and 2+.Keywords
This publication has 4 references indexed in Scilit:
- Mechanism and Kinetics for the Formation of Uranium Mononitride by the Reaction of Uranium Dioxide with Carbon and NitrogenJournal of the American Ceramic Society, 1978
- Layer-like cation ordering in a perovskite-type compound Ca3(CaTa2)O9 with monoclinic symmetryMaterials Research Bulletin, 1976
- Über Perowskitphasen in den Systemen AO-SE2O3-UO2.x mit A = Erdalkali und SE = Seltene Erden, La und Y. IV. Verbindungen der Zusammensetzung Sr2SE0,67UO5,5 und Sr2SE0,67UO6Zeitschrift für anorganische und allgemeine Chemie, 1973
- Über Perowskitphasen in den Systemen BaO–SE2O3–UO2,x mit SE = Seltene Erden, La und Y. I. Verbindungen der Zusammensetzung Ba2SE0,67UO6 und Ba2SE0,67UO5,5Zeitschrift für anorganische und allgemeine Chemie, 1972