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SURFACE AND BULK PROPERTIES OF HOT-PRESSED PBMO6S8 SUPERCONDUCTOR STUDIED BY AUGER-ELECTRON SPECTROSCOPY AND CALORIMETRY

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Title SURFACE AND BULK PROPERTIES OF HOT-PRESSED PBMO6S8 SUPERCONDUCTOR STUDIED BY AUGER-ELECTRON SPECTROSCOPY AND CALORIMETRY
 
Creator SELVAM, P
CORS, J
DECROUX, M
FISCHER, O
 
Subject lattice instability
chevrel phases
samples
snmo6s8
eumo6s8
wires
pb
 
Description A direct observation of the grain-boundary phases for several well-characterized hot-pressed PbMo6S8 samples were made by Auger electron spectroscopy. The surface elemental concentrations are completely different when compared to its bulk composition. The thickness of this altered composition is in the range 100-200 Angstrom gradually increasing with increase in hot-pressing temperature, Also, evidence of segregation of impurities, such as carbon and SiOx, to the grain-boundaries were noticed for some of the samples. Calorimetric experiments show a continuous broadening and a reduction in amplitude of the specific heat anomaly at T-C. This in terms of superconducting volume fraction indicates a T-C distribution in the range 9-15 K. Such an observation can be related to the local inhomogeneities with respect to the ternary composition, i.e., a deviation from ideal stoichiometry, PbMo6S8. The results are discussed in conjunction with X-ray diffraction, scanning electron microscope, and energy dispersive X-ray analysis. By considering the grain-boundary phases and the calorimetric observation of inhomogeneities, a plausible explanation is given for the low critical current densities in these materials.
 
Publisher SPRINGER VERLAG
 
Date 2011-08-30T10:18:20Z
2011-12-26T12:58:53Z
2011-12-27T05:49:35Z
2011-08-30T10:18:20Z
2011-12-26T12:58:53Z
2011-12-27T05:49:35Z
1995
 
Type Article
 
Identifier APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING, 60(5), 459-465
0721-7250
http://dx.doi.org/10.1007/BF01538770
http://dspace.library.iitb.ac.in/xmlui/handle/10054/12282
http://hdl.handle.net/10054/12282
 
Language en