Publication: Reversible Valence Transition Eu-3+ ? Eu-2+ ? Eu-3+ in EuxEux Ox (2)+ (3)+ (M = Ti, Zr, Hf) 1-MO3+x /2 : An Analysis of XAFS and XRD Data
Дата
2022
Авторы
Menushenkov, A. P.
Popov, V. V.
Kuznetsov, A. V.
Molokova, A. Y.
Yastrebtsev, A. A.
Gaynanov, B. R.
Rudakov, S. G.
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Аннотация
The regularities of completely reversible valence transition Eu3+. Eu2+. Eu3+ in complex europium oxides have been investigated using a combination of X-ray diffraction (XRD) and X-ray absorption spectroscopy (XANES + EXAFS) synchrotron methods. The influence of the type of M4+ cations on the reduction and oxidation, as well as the formation and evolution of the crystalline and local structure of the (M = Ti, Zr, Hf) compounds is established. It is shown that oxidation of initially reduced Eu2+MO3 samples leads to the formation of mixed-valence (MV) state Eu2+/Eu3+ with inhomogeneous charge distribution, causing a phase transition with formation of partially amophized intermediate metastable phases Eu3+MO3.5 having a monoclinic structure (sp. gr..1211). An increase in the oxidative annealing temperature to 1000 degrees. facilitates further phase transition with the formation of stable cubic phases Eu M2O7.
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Reversible Valence Transition Eu-3+ ? Eu-2+ ? Eu-3+ in EuxEux Ox (2)+ (3)+ (M = Ti, Zr, Hf) 1-MO3+x /2 : An Analysis of XAFS and XRD Data / Menushenkov, A. P. [et al.] // Crystallography Reports. - 2022. - 67. - № 6. - P. 918-930. - 10.1134/S1063774522060177
URI
https://www.doi.org/10.1134/S1063774522060177
https://www.scopus.com/record/display.uri?eid=2-s2.0-85188738651&origin=resultslist
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https://openrepository.mephi.ru/handle/123456789/28465
https://www.scopus.com/record/display.uri?eid=2-s2.0-85188738651&origin=resultslist
http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=Alerting&SrcApp=Alerting&DestApp=WOS_CPL&DestLinkType=FullRecord&UT=WOS:000931638000016
https://openrepository.mephi.ru/handle/123456789/28465