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Mixed valency and site-preference chemistry for cerium and its compounds: A predictive density-functional theory study

TitleMixed valency and site-preference chemistry for cerium and its compounds: A predictive density-functional theory study
Publication TypeJournal Article
Year of Publication2014
AuthorsAlam, A, Johnson, DD
JournalPhysical Review B
Volume89
Pagination235126
Date Published06
Type of ArticleArticle
ISBN Number1098-0121
Accession NumberWOS:000338516300004
Keywordsce, systems, total-energy calculations, transition, wave basis-set
Abstract

problem involving two valences with competing and numerous site-occupancy configurations. We use density-functional theory with Hubbard U (i.e., DFT+U) to evaluate the effective valence and predict properties, including controlling the valence by pseudoternary alloying. For Ce and its compounds, such as (Ce, La)(2)(Fe,Co)(14)B permanent magnets, we find a stable mixed-valent alpha state near the spectroscopic value of nu(s) = 3.53. Ce valency in compounds depends on its steric volume and local chemistry. For La doping, Ce valency shifts towards gamma-like Ce3+, as expected from steric volume; for Co doping, valency depends on local Ce-site chemistry and steric volume. Our approach captures the key origins of anomalous valency and site-preference chemistry in complex compounds.

DOI10.1103/PhysRevB.89.235126
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