AN APFIM/FEM INVESTIGATION OF PLANAR DEFECTS IN HIGH TEMPERATURE SUPERCONDUCTORS

1988 ◽  
Vol 49 (C6) ◽  
pp. C6-447-C6-452
Author(s):  
M. K. MILLER ◽  
A. J. MELMED ◽  
K. L. MORE
Keyword(s):  
High Temperature ◽  
High Temperature Superconductors ◽  
Planar Defects

Site Exchange in High Temperature Superconductors

1987 ◽  
Vol 99 ◽  
Author(s):  
D. J. Li ◽  
H. Shibahara ◽  
J. P. Zhang ◽  
L. D. Marks
Keyword(s):  
Heavy Metals ◽  
High Temperature ◽  
Grain Boundary ◽  
High Temperature Superconductors ◽  
Planar Defects ◽  
Electron Microscopical Analysis ◽  
Site Exchange ◽  
Copper Sites ◽  
Electron Microscopical ◽  
Brown Powder

ABSTRACTElectron microscopical analysis of brown powders of composition YBa2Cu3O6.5 produced by oil quenching and conventionally produced orthorhombic GdBa2Cu3O7-δ show in both cases clear evidence for site exchange both between the different heavy metals and the heavy metals and the copper sites. For instance, the brown powder is a mixture of phases which are based upon two trigonal phases, both with a=0.536 and c=0.666 nm, one with the Y atoms stacked on the (111) planes of the parent perovskite structure and the second where the Y atoms of this structure have interchanged with one of the copper sites. The GdBa2Cu3O7-δ, material shows numerous planar defects on (001) planes which can be understood as copper rich regions with additional copper planes in the Ba or Gd sites. These results, together with earlier reports of order-disorder in YBa2Cu3O7-δ, strongly indicate that there exist ordering energies in these materials which may be important with respect to the current indications of the important of grain boundary phases in degrading the performance of some superconductors.

A study by GC-MS of the decomposition of precursors for the MOCVD of high temperature superconductors

2002 ◽  
Vol 12 (4) ◽  
pp. 85-92
Author(s):  
O. V. Lopaeva ◽  
M. L. Hitchman ◽  
S. H. Shamlian ◽  
D. R. Watson
Keyword(s):  
High Temperature ◽  
High Temperature Superconductors
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