Interactions of Ba{sub 2}YCu{sub 3}O{sub 6+y} with the Gd{sub 3}NbO{sub 7} buffer layer in coated conductors

Journal Article · Mon Mar 15 00:00:00 EDT 2010 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2010.01.006· OSTI ID:21372534

Wong-Ng, W ^[1]; Yang, Z ^[1]; Kaduk, J A ^[2]; Cook, L P ^[1]; Paranthaman, M ^[3]

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1. Ceramics Division, National Institute of Standards and Technology, Gaithersburg, MD 20899 (United States)
2. INEOS Technology, Naperville, IL 60566-7011 (United States)
3. Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States)

A systematic study of the chemical interaction of Ba{sub 2}YCu{sub 3}O{sub 6+y} and Gd{sub 3}NbO{sub 7} was conducted under two processing conditions: purified air (21% p{sub o{sub 2}}), and 100 Pa p{sub o{sub 2}} (0.1% p{sub o{sub 2}}). Phases present along the pseudo-binary join Ba{sub 2}YCu{sub 3}O{sub 6z} and Gd{sub 3}NbO{sub 7} were found to be in two five-phase volumes within the BaO-1/2 Y{sub 2}O{sub 3}-1/2 Gd{sub 2}O{sub 3}-Nb{sub 2}O{sub 5}-CuO{sub y} system. Three common phases that are present in all samples are (Y,Gd){sub 2}Cu{sub 2}O{sub 5}, Ba(Y,Gd){sub 2}CuO{sub 5} and Cu{sub 2}O or CuO (depending on the processing conditions). The assemblies of phases can be categorized in three regions, with Ba{sub 2}YCu{sub 3}O{sub 6+y}: Gd{sub 3}NbO{sub 7} ratios of (I)<5.5:4.5; (II)=5.5:4.5; and (III)>5.5:4.5. The lowest melting temperature of the system was determined to be {approx}938 deg. C in air, and 850 deg. C at 100 Pa p{sub o{sub 2}}. Structure determinations of two selected phases, Ba{sub 2}(Gd{sub x}Y{sub 1-x})NbO{sub 6} (Fm3-barm, No. 225), and (Gd{sub x}Y{sub 3-x})NbO{sub 7} (C222{sub 1}, No. 20 and Ccmm, No. 63), were completed using the X-ray Rietveld refinement technique. Reference X-ray powder diffraction patterns for selected phases of Ba{sub 2}(Gd{sub x}Y{sub 1-x})NbO{sub 6} (x=0.2, 0.4, 0.6, and 0.8) and (Gd{sub x}Y{sub 3-x})NbO{sub 7} (x=0.6, 1.2, 1.8, 2.4 and 3) have been prepared for inclusion in the Powder Diffraction File (PDF). - Graphical abstract: Crystal structure for (Gd{sub x}Y{sub 3-x})NbO{sub 7} showing the partial layered feature. The alternate stacking of distorted NbO{sub 6} octahedra and (Gd,Y)O{sub 7} polyhedra are illustrated. The (Gd,Y)O{sub 8} polyhedra are omitted for clarity.

• OSTI ID: 21372534
• Journal Information: Journal of Solid State Chemistry, Vol. 183, Issue 3; Other Information: DOI: 10.1016/j.jssc.2010.01.006; PII: S0022-4596(10)00007-1; Copyright (c) 2010 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; ISSN 0022-4596
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
BARIUM COMPOUNDS
BARIUM OXIDES
COPPER OXIDES
CUBIC LATTICES
CUPRATES
GADOLINIUM COMPOUNDS
GADOLINIUM OXIDES
INTERACTIONS
LAYERS
MELTING POINTS
NIOBATES
NIOBIUM OXIDES
SUPERCONDUCTORS
X RADIATION
X-RAY DIFFRACTION
YTTRIUM COMPOUNDS
YTTRIUM OXIDES
ALKALINE EARTH METAL COMPOUNDS
CHALCOGENIDES
COHERENT SCATTERING
COPPER COMPOUNDS
CRYSTAL LATTICES
CRYSTAL STRUCTURE
DIFFRACTION
ELECTROMAGNETIC RADIATION
IONIZING RADIATIONS
NIOBIUM COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
RADIATIONS
RARE EARTH COMPOUNDS
REFRACTORY METAL COMPOUNDS
SCATTERING
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENT COMPOUNDS
TRANSITION TEMPERATURE