An experimental and theoretical study of Ni impurity centers in Ba0.8Sr0.2TiO3статья
Информация о цитировании статьи получена из
Web of Science,
Scopus
Статья опубликована в журнале из списка Web of Science и/или Scopus
Дата последнего поиска статьи во внешних источниках: 17 октября 2017 г.
Аннотация:The local environment and the charge state of a nickel impurity in cubic Ba0.8Sr0.2TiO3 are studied by XAFS spectroscopy. According to the XANES data, the mean Ni charge state is 2.5+. An analysis of the EXAFS spectra and their comparison with the results of first-principle calculations of the defect geometry suggest that Ni2+ ions are in a high-spin state at the B sites of the perovskite structure and the difference of charges of Ni2+ and Ti4+ is mainly compensated by distant oxygen vacancies. In addition, a considerable amount of nickel in the sample is in a second phase BaNiO3-\delta. The measurements of the lattice parameter show a decrease in the unit cell volume upon doping, which can indicate the existence of
a small amount of Ni4+ ions at the B sites.