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Effect of vanadium doping on the electrical and structural properties of GdBa 2 Cu 3– x V x O 7– δ
Author(s) -
Javanmard H.,
Bazargan S.,
Akhavan M.
Publication year - 2008
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.200743404
Subject(s) - tetragonal crystal system , vanadium , orthorhombic crystal system , electrical resistivity and conductivity , crystal structure , crystallography , doping , superconductivity , materials science , octahedron , analytical chemistry (journal) , phase (matter) , chemistry , condensed matter physics , metallurgy , physics , optoelectronics , organic chemistry , chromatography , electrical engineering , engineering
The compounds with composition GdBa 2 Cu 3– x V x O 7– δ and x = 0.0, 0.05, 0.1, 0.15, 0.2 and 0.3 have been prepared by the solid‐state reaction method. The XRD spectra indicate single‐phase formation of the compounds. The transition temperature decreases considerably with vanadium concentration to T c = 26.4K for x = 0.3. The host sample is in the orthorhombic phase, but by increasing the V content the structure approaches the tetragonal phase, and for x = 0.3 the structure is nearly tetragonal. The normal state resistivity has been compared with 2D‐VRH, 3D‐VRH, and CG regimes, which shows that the 2D‐VRH and CG are in better agreement for our samples. The localization length is calculated for the 2D‐VRH, which shows a decrease with doping, and for x = 0.15 this drop is significant. Based on our preparation conditions, V is likely to remain as V 4+ in the compound, and because of the high tendency of V 4+ for achieving the octahedral structure, it appears that vanadium enters the chains, and accounts for the observed changes in the crystal structure and the superconducting properties. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)