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Crystal Chemistry and Phase Equilibrium Studies of the BaO(BaCO 3 )–½R 2 O 3 –CuO x Systems in Air: VI, R = Neodymium
Author(s) -
WongNg Winnie,
Cook Lawrence P.,
Paretzkin Boris,
Hill Michael D.,
Stalick Judith K.
Publication year - 1994
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1994.tb04605.x
Subject(s) - orthorhombic crystal system , tetragonal crystal system , solid solution , phase diagram , stoichiometry , phase (matter) , x ray crystallography , analytical chemistry (journal) , crystal structure , crystal chemistry , chemistry , crystallography , neodymium , crystal (programming language) , diffraction , materials science , physics , laser , programming language , organic chemistry , chromatography , computer science , optics
Crystal chemistry and subsolidus phase equilibrium studies of the Ba‐Nd‐Cu‐O system near the CuO and Nd 2 O 3 corners have been carried cut 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‐ T c superconductor phase, and has the formula Ba 2–x Nd 1+x Cu 3 O 6+z , where × < ≅ 0.7. At the ideal compound stoichiometry of Ba 2 NdCu 3 O 6+z , the transformation from the high‐ T c orthorhombic to tetragonal phase occurs at 550°–575°C in air. This temperature varies as a function of composition, and at x ≅ 0.2 to 0.3 it occurs at 950°C. The second solid solution is the non‐superconducting “brown phase” represented by Ba 2+2x ‐Nd 4–2x Cu 2–x O 10–2z 0 ≤ x ≤ 0.1. Preliminary phase diagrams of the BaO–Nd 2 O 3 and Nd 2 O 3 –CuO x systems are also presented. Standard X‐ray diffraction patterns of BaNd 2 –CuO 5 and (Nd 1.9 Ca 0.1 )CuO 4–z are provided.