Сибирский федеральный университет

Тип публикации: статья из журнала

Год издания: 2020

Идентификатор DOI: 10.1016/j.ceramint.2020.12.030

Ключевые слова: magnetic properties, rare-earth substituted cobalt oxides, ruddlesden‒popper phase, thermoelectric oxide materials

Аннотация: ―A new anion-deficient Sr2.4Dy0.6Co2O7‒δ (δ = 0.33–1.1) perovskite phase with a structure of the A3B2O7 Raddlesden‒Popper homologous series has been obtained by the solid-state synthesis in the reducing/oxidizing atmosphere and its structural characterization has been performed by the Rietveld refinement of the X-ray powder diffraction data. It has been stablished that the Sr2.4Dy0.6Co2O7‒δ compound (sp. gr. I4/mmm) has parameters of a = b = 3.8526(1) and c = 19.9431(7) Å in the reduced form (δ = 1.1) and a = b = 3.8086(1) and c = 19.9190(6) Å in the oxidized form (δ ≈ 0.33) and oxygen vacancies occupy mainly the sites linking CoO5 polyhedra inside two perovskite layers. It has been established using differential scanning calorimetry and thermogravimetry that, at T < 530 K, the synthesized phase is stable against the inert and oxidizing atmosphere; at higher temperatures, the Sr2.4Dy0.6Co2O7-δ compound can reversibly absorb/release oxygen. The magnetic properties of the Sr2.4Dy0.6Co2O6.09 compound have been investigated in the temperature range of 10–400 K and described in terms of the formation of dimers, in which the Co3+‒Co3+ and Co2+‒Co2+ ion pairs antiferromagnetically interact and are in the nonmagnetic ground state. The electrical conductivity and the Seebeck coefficient have been measured in air in the temperature range from 300 to 800 K. An observed sharp decrease in the Seebeck coefficient of the Sr2.4Dy0.6Co2O7-δ compound and the change in its sign near 700 K have been attributed to the transition of cobalt ions to the Co3+ state and the charge disproportionation of Co3+ ions to Co2+ and Co4+ ones. © 2020 Elsevier Ltd and Techna Group S.r.l.

Журнал: Ceramics International

ISSN журнала: 02728842

Издатель: Elsevier Ltd

• Dudnikov V.A. (Russian Acad Sci, Krasnoyarsk Sci Ctr, Kirensky Inst Phys, Siberian Branch, Krasnoyarsk 660036, Russia)
• Orlov Yu S. (Russian Acad Sci, Krasnoyarsk Sci Ctr, Kirensky Inst Phys, Siberian Branch, Krasnoyarsk 660036, Russia; Siberian Fed Univ, Krasnoyarsk 660041, Russia)
• Solovyov L.A. (Russian Acad Sci, Krasnoyarsk Sci Ctr, Inst Chem & Chem Technol, Siberian Branch, Krasnoyarsk 660036, Russia)
• Vereshchagin S.N. (Russian Acad Sci, Krasnoyarsk Sci Ctr, Inst Chem & Chem Technol, Siberian Branch, Krasnoyarsk 660036, Russia)
• Gavrilkin S.Yu (Russian Acad Sci, Lebedev Phys Inst, Moscow 119991, Russia)

• Scopus
• Web of Science Core Collection
• Ядро РИНЦ (eLIBRARY.RU)