Crystal chemistry and phase equilibrium studies of the BaO(BaCO[sub 3])-[1/2]R[sub 2]O[sub 3]-CuO[sub x] systems in air; 6: R = neodymium

Journal Article · Thu Sep 01 00:00:00 EDT 1994 · Journal of the American Ceramic Society; (United States)

DOI:https://doi.org/10.1111/j.1151-2916.1994.tb04605.x· OSTI ID:7154727

Wong-Ng, W; Cook, L P; Paretzkin, B; Hill, M D; Stalick, J K ^[1]

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1. National Inst. of Standards and Technology, Gaithersburg, MD (United States). Materials Science and Engineering Lab.

Crystal chemistry and subsolidus phase equilibrium studies of the Ba-Nd-Cu-O system near the CuO and Nd[sub 2]O[sub 3] corners have been carried out at 950 C in air. Two solid-solution series have been identified in the Ba-Nd-Cu-O system. The first series involves the high-[Tc] superconductor phase, and has the formula Ba[sub 2[minus]x]Nd[sub 1+x]Cu[sub 3]O[sub 6+z], where x < [approx] 0.7. At the ideal compound stoichiometry of Ba[sub 2]NdCu[sub 3]O[sub 6+z], the transformation from the high-[Tc] orthorhombic to tetragonal phase occurs at 550--575 C in air. This temperature varies as a function of composition, and at x [approx] 0.2 to 0.3 it occurs at 950 C. The second solid solution is the non-superconducting brown phase'' represented by Ba[sub 2+2x]Nd[sub 4[minus]2x]Cu[sub 2[minus]x]O[sub 10[minus]2z], 0 [<=] x [<=] 0.1. Preliminary phase diagrams of the BaO-Nd[sub 2]O[sub 3] and Nd[sub 2]O[sub 3]-CuO[sub x] systems are also presented. Standard X-ray diffraction patterns of BaNd[sub 2]CuO[sub 5] and (Nd[sub 1.9]Ca[sub 0.1])CuO[sub 4[minus]z] are provided.

• OSTI ID: 7154727
• Journal Information: Journal of the American Ceramic Society; (United States), Vol. 77:9; ISSN 0002-7820
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
BARIUM OXIDES
PHASE STUDIES
COPPER OXIDES
NEODYMIUM OXIDES
CRYSTAL-PHASE TRANSFORMATIONS
HIGH-TC SUPERCONDUCTORS
PHASE DIAGRAMS
ALKALINE EARTH METAL COMPOUNDS
BARIUM COMPOUNDS
CHALCOGENIDES
COPPER COMPOUNDS
DIAGRAMS
NEODYMIUM COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PHASE TRANSFORMATIONS
RARE EARTH COMPOUNDS
SUPERCONDUCTORS
TRANSITION ELEMENT COMPOUNDS
360202* - Ceramics
Cermets
&amp; Refractories- Structure &amp; Phase Studies