The defect structure and chemical lattice strain of the double perovskites Sr2BMoO6-delta (B = Mg, Fe) / Tsvetkov D. S.,Ivanov I. L.,Malyshkin D. A.,Steparuk A. S.,Zuev A. Yu. // DALTON TRANSACTIONS. - 2016. - V. 45, l. 32. - P. 12906-12913.

ISSN/EISSN:

1477-9226 / 1477-9234

Type:

Article

Abstract:

The defect structure of B-site ordered double perovskites Sr2BMoO6-delta was analyzed. The defect structure model was proposed and successfully verified using data on oxygen nonstoichiometry of Sr2MgMoO6-delta and Sr2FeMoO6-delta. As a result, equilibrium constants of the defect reactions involved were estimated. Fe and Mo in Sr2FeMoO6-delta were found to be in the mixed oxidation state close to +2.5 and +5.5, respectively. Chemical strain of the Sr2FeMoO6-delta double perovskite lattice was studied by in situ high temperature XRD at 1100 degrees C depending on pO(2). Parameter a of the Sr2FeMoO6-delta cubic cell was found to increase with decreasing pO(2) because of lattice chemical expansion. The tetragonal polymorph of Sr2FeMoO6-delta was shown to exhibit transversal isotropy with respect to chemical expansion. It was also found that its crystal lattice expands in the ab-plane and simultaneously contracts along the c-axis when the oxygen content in the double perovskite decreases. In order to describe the degree of anisotropy of chemical strain a new phenomenological coefficient was introduced. This coefficient was shown to affect both the magnitude and change direction of an oxide cell volume caused by its reduction/oxidation. Excellent agreement between the chemical expansion along the a-axis calculated for both polymorphs of Sr2FeMoO6-delta according to the model recently developed and that measured experimentally was shown. Chemical contraction observed along the c-axis with a decreasing oxygen content in the tetragonal polymorph was also found to coincide completely with that calculated using the approach developed in the present study.

Author keywords:

ORDERED DOUBLE-PEROVSKITE; SITU NEUTRON-DIFFRACTION; MAGNETIC-PROPERTIES; INDUCED EXPANSION; ANTISITE DEFECTS; OXYGEN VACANCIES; SR2FEMOO6; VALENCE; IRON; NONSTOICHIOMETRY

DOI:

10.1039/c6dt02513g

Web of Science ID:

ISI:000381478500037

Соавторы в МНС:

Другие поля

Поле	Значение
Month	AUG 28
Publisher	ROYAL SOC CHEMISTRY
Address	THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND
Language	English
EISSN	1477-9234
Keywords-Plus	ORDERED DOUBLE-PEROVSKITE; SITU NEUTRON-DIFFRACTION; MAGNETIC-PROPERTIES; INDUCED EXPANSION; ANTISITE DEFECTS; OXYGEN VACANCIES; SR2FEMOO6; VALENCE; IRON; NONSTOICHIOMETRY
Research-Areas	Chemistry
Web-of-Science-Categories	Chemistry, Inorganic \& Nuclear
Author-Email	dmitry.tsvetkov@urfu.ru
ResearcherID-Numbers	Zuev, Andrey/E-6220-2014 Malyshkin, Dmitry/M-2195-2016 Ivanov, Ivan/E-7879-2017 Tsvetkov, Dmitry/N-2491-2016
ORCID-Numbers	Malyshkin, Dmitry/0000-0002-8828-4882 Ivanov, Ivan/0000-0001-9277-7543
Funding-Acknowledgement	Russian Foundation for Basic Research {[}15-33-20978]
Funding-Text	This work was supported by the Russian Foundation for Basic Research (Grant No. 15-33-20978).
Number-of-Cited-References	37
Usage-Count-Last-180-days	9
Usage-Count-Since-2013	25
Journal-ISO	Dalton Trans.
Doc-Delivery-Number	DT4VE