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Crystal and Defect Structure of Nd 1.9 Ce 0.1 CuO 4±y
Author(s) -
Petrov Alexander N.,
Zuev Andrey Yu.,
Rodionova Tatjana P.,
Voronin Vladimir I.
Publication year - 1999
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.1151-2916.1999.tb01870.x
Subject(s) - thermogravimetry , tetragonal crystal system , oxygen , cerium , crystallography , crystal structure , neutron diffraction , analytical chemistry (journal) , crystal (programming language) , chemistry , single crystal , materials science , interstitial defect , x ray crystallography , diffraction , inorganic chemistry , doping , organic chemistry , chromatography , physics , optoelectronics , optics , computer science , programming language
The crystal and defect structure of neodymium cerium cu‐prate (Nd 1.9 Ce 0.1 CuO 4±y ) has been studied as a function of temperature (1200–1500 K) and oxygen pressure (10 0 –10 3 atm) via X‐ray diffractometry, powder neutron diffraction, and thermogravimetry methods. The oxygen nonstoichiom‐etry changes from oxygen‐excess (positive y values) to oxygen‐ deficient oxides (negative y values). The absolute values of oxygen nonstoichiometry y are calculated from the neu‐tron diffraction and thermogravimetry data. The materials adopt the tetragonal structure (space group I 4/ mmm ). A defect model is proposed for Nd 2‐x Ce x CuO 4±y . It is con‐cluded that oxygen vacancies V Ö (which occupy O(1) crys‐tallographic positions (in planes)) and interstitial oxygen O(i (which occupy O(3) “apical” positions) are present simultaneously. Gaseous oxygen intercalates into the Nd 1.9 Ce 0.1 CuO 4±y crystals and replaces oxygen vacancies in the O(1) position and interstitial oxygen atoms in the O(3) positions. The theoretical model and the experimental data are in good agreement with each other, and the equilibrium constants of defect formation have been calculated.