ISSN:
1573-2746
Keywords:
Y2BaCuO5-YBa2Cu3O7-x interface
;
point defeets
;
flux pinning
;
cation nonstoichiometry
;
grain boundary chemistry
;
oxygen deficiency
;
hole density
;
grain boundary misorientation
;
high-resolution transmission electron microscopy (HRTEM)
;
energy dispersive X-ray spectroscopy (EDS)
;
electron energy-loss spectroscopy (EELS)
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
,
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
,
Physics
Notes:
Abstract Y2BaCuO5YBa2Cu3O7-x (Y211/Y123) interfaces in melt-processed YBa2Cu3O7-x were studied by high-resolution transmission electron microscopy and energy dispersive X-ray spectroscopy. Yttrium enrichment and barium depletion were observed locally at the Y211/Y123 interfaces where Y123 (001) facets were present. This effect may be interpreted as the result of lattice substitution of Ba by Y near these interfaces. Cation nonstoichiometry was found near Y211/Y123 interfaces where liquid phases (Cu-Ba-O) were present. This chemical disorder introduces numerous point defects in the Y123, and these defects may act as additional pinning sites alongwith stacking faults. A comparison of grain boundary (GB) chemical composition in polycrystalline YBa2Cu3O7-x and YBa2Cu4O8(Y124), studied using nanoprobe parallel-detection electron energy-loss spectroscopy (EELS), is presented. The studies of Y124 show that stoichiometric grain boundaries can also form weak links between superconducting grains. It is suggested that weak-link behavior is determined largely by misorientation at grain boundaries.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00188702
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