Open AccessPhase structures and local electron structures of Gd-doped YBa2Cu3O7－δ systems
Author(s) -
Zhenping Chen,
Xue Yun-Cai,
SU Yuling,
Gong Shi-Cheng,
Jincang Zhang
Publication year - 2005
Publication title -
wuli xuebao
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.199
H-Index - 47
ISSN - 1000-3290
DOI - 10.7498/aps.54.5382
Subject(s) - orthorhombic crystal system , superconductivity , cuprate , materials science , annihilation , condensed matter physics , positron annihilation , doping , positron , phase (matter) , crystal (programming language) , electronic structure , single crystal , electron , crystal structure , crystallography , nuclear magnetic resonance , physics , nuclear physics , chemistry , quantum mechanics , computer science , programming language
The Gd substituted Y1-xGdxBa2Cu3O7-δ systems are studied systematically by positron annihilation and x-r ay diffraction. The x-ray results show that the crystal parameters and crystal v olume of the systems increase with the increase of Gd content. However, all the substituted samples maintain the single orthorhombic phase as YBa2Cu3O7-δ (YBCO) sample does. The positron annihilation result s show that positron lifetimes depend on the Gd content strongly. According to t he positron annihilation result, the local electronic density on Cu-O chain is c alculated. The result shows the local electronic density decreases with the incr ease of the Gd content, while the Tc increases with the decrease of t he local electronic density. The relationship between the local electronic densi ty and superconductivity is different from the substitution on Cu site, which ma y be one of the reasons why the mixed rare earth cuprate superconductor has a hi gher critical electric current density than the YBCO. These experimental results give the corresponding positron experiment data for the application of cuprate superconductors and study of the mechanism.