Negative magnetization, shielding current effect and divalent manganese in CaMn1-xTaxO3 manganites

Авторы: Ulyanov A N A.N., Yang Dong-Seok, Savilov S.V.
Журнал: Journal of Alloys and Compounds
Том: 967
Год издания: 2023
Издательство: Elsevier BV
Местоположение издательства: Netherlands
Номер статьи: 171686
DOI: 10.1016/j.jallcom.2023.171686
Аннотация: Crystal and electronic structures, and magnetic properties of polycrystalline tantalum substituted manganites CaMn1-xTaxO3 (x = 0.00, 0.03, 0.06, 0.09 and 0.12) were studied by x-ray diffraction, x-ray absorption near edge spectroscopy (XANES) at Mn K-edge, and by magnetization measurements. Large changes of cell volume and magnetic transition temperature, in addition to shift of Mn K-edge spectra and change of shape of XANES spectra, indicate the existence of Mn3+ as well as Mn2+ species induced by the substitution of Mn4+ by Ta5+. Cell parameters and cell volume increase with increasing x because the Mn3+, Mn2+ and Ta5+ ions are larger that substituted Mn4+ ion. According to XANES results, at least the x=0.00 sample is oxygen deficient. The negative magnetization was observed in the CaMnO3-δ sample, and a possible explanation of the phenomenon is given considering two canted (almost antiferro)magnetic sublattices and a shielding current, associated with the itinerant eg electrons, induced by the oxygen vacancies.
Добавил в систему: Ульянов Александр Николаевич

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