Local dynamics and structure of pure and Ta substituted(K1−xNax)NbO3from first principles calculations

Autor:	David J. Singh, Malliga Suewattana
Rok vydání:	2010
Předmět:	Permittivity Crystallography Distribution function Materials science Condensed matter physics Curie temperature Dielectric Condensed Matter Physics Piezoelectricity Electronic Optical and Magnetic Materials Natural bond orbital Perovskite (structure) Solid solution
Zdroj:	Physical Review B. 82
ISSN:	1550-235X 1098-0121
DOI:	10.1103/physrevb.82.014114
Popis:	The local structure and dynamics of piezoelectric K{sub 1-x}Na{sub x}NbO{sub 3} perovskite solid solutions with and without partial Ta substitution at x = 0.5 are investigated using first principles calculations for supercells. The results are analyzed locally using the dynamical pair distribution functions. The local structures for Ta-substituted material show smaller off-centering of Ta compared to Nb. In addition, the dynamics of the relaxed structure indicate softer Nb force constants relative to Ta even though the Nb has shorter O nearest-neighbor distances than Ta. These results are discussed in relation to experimental measurements which show a decrease in Curie temperature and an increase in dielectric constant when Ta is partially substituted into K{sub 1-x}Na{sub x}NbO{sub 3}.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::3134af49382459bdf5ad57db3a5e3b25 https://doi.org/10.1103/physrevb.82.014114 Zobrazit plný text záznamu