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Superconductivity in the (Yba 2 Cu 3 ) 1−x Na x O 7−δ System
Author(s) -
Chen Christina H.,
Kumar Binod
Publication year - 1994
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1994.tb07262.x
Subject(s) - tetragonal crystal system , orthorhombic crystal system , superconductivity , meissner effect , materials science , doping , crystallite , analytical chemistry (journal) , crystallography , transition temperature , crystal structure , condensed matter physics , chemistry , physics , optoelectronics , chromatography
The (YBa 2 Cu 3 ) 1−x Na x O 7–δ system in the range of x = 0–0.8 was investigated. Experimental data suggest that the sodium doping with x 0.26 does not affect the critical transition temperature T c , and the crystal structure maintains the orthorhombic lattice with a slightly smaller unit cell. However, sodium doping increases the sintering and grain growth kinetics, resulting in a higher superconducting phase volume and an enhanced Meissner effect. It also lowers the processing temperaturel. The experimental data also suggest that the sodium atoms diffuse into the superconducting YBa 2 Cu 3 O 7−δ crystallites, which stabilizes the orthorhombic phase. The transition temperature (ortho‐rhombic to tetragonal) in sodium‐doped materials increases with the increasing concentration of sodium.