Electronic structure and x-ray magnetic circular dichroism in A₂CrB′O₆ (A = Ca, Sr; B′ = W, Re, and Os) oxides

A systematic electronic structure study of A₂CrB′O₆ (A = Ca, Sr; B′ = W, Re, and Os) has been performed by employing the local spin-density approximation (LSDA) as well as the GGA and LSDA + U methods using the fully relativistic spin-polarized Dirac linear muffin-tin orbital band-structure method....

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Veröffentlicht in:Физика низких температур
Datum:2017
Hauptverfasser: Antonov, L.V., Bekenov, V.N.
Format: Artikel
Sprache:English
Veröffentlicht: Фізико-технічний інститут низьких температур ім. Б.І. Вєркіна НАН України 2017
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Online Zugang:https://nasplib.isofts.kiev.ua/handle/123456789/129497
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Zitieren:Electronic structure and x-ray magnetic circular dichroism in A₂CrB′O₆ (A = Ca, Sr; B′ = W, Re, and Os) oxides / V.N. Antonov L.V. Bekenov // Физика низких температур. — 2017. — Т. 43, № 5. — С. 724-737. — Бібліогр.: 83 назв. — англ.

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Digital Library of Periodicals of National Academy of Sciences of Ukraine
id nasplib_isofts_kiev_ua-123456789-129497
record_format dspace
spelling Antonov, L.V.
Bekenov, V.N.
2018-01-19T18:57:24Z
2018-01-19T18:57:24Z
2017
Electronic structure and x-ray magnetic circular dichroism in A₂CrB′O₆ (A = Ca, Sr; B′ = W, Re, and Os) oxides / V.N. Antonov L.V. Bekenov // Физика низких температур. — 2017. — Т. 43, № 5. — С. 724-737. — Бібліогр.: 83 назв. — англ.
0132-6414
ACS: 75.50.Cc, 71.20.Lp, 71.15.Rf
https://nasplib.isofts.kiev.ua/handle/123456789/129497
A systematic electronic structure study of A₂CrB′O₆ (A = Ca, Sr; B′ = W, Re, and Os) has been performed by employing the local spin-density approximation (LSDA) as well as the GGA and LSDA + U methods using the fully relativistic spin-polarized Dirac linear muffin-tin orbital band-structure method. We investigated the effects of the subtle interplay among the spin-orbit coupling, electron correlations, and lattice distortion on the electronic structure of the double perovskites. First principles calculations predict that Sr₂CrOsO₆ is (before considering spin-orbit coupling) actually a ferrimagnetic semimetal with precisely compensating spin moments, or spin-asymmetric compensated semimetallic ferrimagnet in which the electrons and holes are each fully polarized and have opposite spin directions, in spite of a zero net moment and hence no macroscopic magnetic field. Spin-orbit coupling degrades this by giving a nonzero total moment, but the band structure is little changed. Therefore, the observed saturation moment of ferrimagnetic Sr ₂CrOsO ₆ is entirely due to spin-orbit coupling. The x-ray absorption spectra and x-ray magnetic circular dichroism at the W, Re, Os, and CrL₂,₃, and Cr and O K edges were investigated theoretically from first principles. A qualitative explanation of the XMCD spectra shape is provided by the analysis of the corresponding selection rules, orbital character and occupation numbers of individual orbitals. The calculated results are in good agreement with experimental data. The complex fine structure of the CrL₂,₃ XAS in Sr₂CrWO₆ and Sr₂CrReO₆ was found to be not compatible with a pure Cr³⁺ valency state. The interpretation demands mixed valent states. We found that possible oxygen vacancies lead to a mixed valency at the Cr site, double peak structure at the CrL₂,₃ edges and reduce the saturation magnetization in Sr₂CrWO₆ and Sr₂CrReO₆.
We are thankful to Dr. A.N. Yaresko for helpful discussions. This work was supported by Science and Technology Center in Ukraine STCU, Project No. 6255.
en
Фізико-технічний інститут низьких температур ім. Б.І. Вєркіна НАН України
Физика низких температур
К 70-летию со дня рождения С.Л. Гнатченко
Electronic structure and x-ray magnetic circular dichroism in A₂CrB′O₆ (A = Ca, Sr; B′ = W, Re, and Os) oxides
Article
published earlier
institution Digital Library of Periodicals of National Academy of Sciences of Ukraine
collection DSpace DC
title Electronic structure and x-ray magnetic circular dichroism in A₂CrB′O₆ (A = Ca, Sr; B′ = W, Re, and Os) oxides
spellingShingle Electronic structure and x-ray magnetic circular dichroism in A₂CrB′O₆ (A = Ca, Sr; B′ = W, Re, and Os) oxides
Antonov, L.V.
Bekenov, V.N.
К 70-летию со дня рождения С.Л. Гнатченко
title_short Electronic structure and x-ray magnetic circular dichroism in A₂CrB′O₆ (A = Ca, Sr; B′ = W, Re, and Os) oxides
title_full Electronic structure and x-ray magnetic circular dichroism in A₂CrB′O₆ (A = Ca, Sr; B′ = W, Re, and Os) oxides
title_fullStr Electronic structure and x-ray magnetic circular dichroism in A₂CrB′O₆ (A = Ca, Sr; B′ = W, Re, and Os) oxides
title_full_unstemmed Electronic structure and x-ray magnetic circular dichroism in A₂CrB′O₆ (A = Ca, Sr; B′ = W, Re, and Os) oxides
title_sort electronic structure and x-ray magnetic circular dichroism in a₂crb′o₆ (a = ca, sr; b′ = w, re, and os) oxides
author Antonov, L.V.
Bekenov, V.N.
author_facet Antonov, L.V.
Bekenov, V.N.
topic К 70-летию со дня рождения С.Л. Гнатченко
topic_facet К 70-летию со дня рождения С.Л. Гнатченко
publishDate 2017
language English
container_title Физика низких температур
publisher Фізико-технічний інститут низьких температур ім. Б.І. Вєркіна НАН України
format Article
description A systematic electronic structure study of A₂CrB′O₆ (A = Ca, Sr; B′ = W, Re, and Os) has been performed by employing the local spin-density approximation (LSDA) as well as the GGA and LSDA + U methods using the fully relativistic spin-polarized Dirac linear muffin-tin orbital band-structure method. We investigated the effects of the subtle interplay among the spin-orbit coupling, electron correlations, and lattice distortion on the electronic structure of the double perovskites. First principles calculations predict that Sr₂CrOsO₆ is (before considering spin-orbit coupling) actually a ferrimagnetic semimetal with precisely compensating spin moments, or spin-asymmetric compensated semimetallic ferrimagnet in which the electrons and holes are each fully polarized and have opposite spin directions, in spite of a zero net moment and hence no macroscopic magnetic field. Spin-orbit coupling degrades this by giving a nonzero total moment, but the band structure is little changed. Therefore, the observed saturation moment of ferrimagnetic Sr ₂CrOsO ₆ is entirely due to spin-orbit coupling. The x-ray absorption spectra and x-ray magnetic circular dichroism at the W, Re, Os, and CrL₂,₃, and Cr and O K edges were investigated theoretically from first principles. A qualitative explanation of the XMCD spectra shape is provided by the analysis of the corresponding selection rules, orbital character and occupation numbers of individual orbitals. The calculated results are in good agreement with experimental data. The complex fine structure of the CrL₂,₃ XAS in Sr₂CrWO₆ and Sr₂CrReO₆ was found to be not compatible with a pure Cr³⁺ valency state. The interpretation demands mixed valent states. We found that possible oxygen vacancies lead to a mixed valency at the Cr site, double peak structure at the CrL₂,₃ edges and reduce the saturation magnetization in Sr₂CrWO₆ and Sr₂CrReO₆.
issn 0132-6414
url https://nasplib.isofts.kiev.ua/handle/123456789/129497
fulltext
citation_txt Electronic structure and x-ray magnetic circular dichroism in A₂CrB′O₆ (A = Ca, Sr; B′ = W, Re, and Os) oxides / V.N. Antonov L.V. Bekenov // Физика низких температур. — 2017. — Т. 43, № 5. — С. 724-737. — Бібліогр.: 83 назв. — англ.
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