Tetragonal to cubic transition of Sr0.8Dy0.2CoO3-δ and oxygen mobility: TG-DSC-XRD study

Описание

Тип публикации: статья из журнала

Год издания: 2021

Идентификатор DOI: 10.1016/j.jallcom.2020.158257

Ключевые слова: ceramics, oxygen mobility, perovskite, phase transitions, thermal analysis, x-ray diffraction

Аннотация: Processes of ordering (d-o) and disordering (o-d) of Sr2+/Dy3+ cations in a single-phase Sr0.8Dy0.2CoO3-δ was investigated by TG-DSC and XRD as a function of heating/cooling rate (β = 2,10,20,50,99 K min−1 and ~50 K/s) in 20% O2-Ar flow. According to DSC data the interconversion of disordered cubic (c) and ordered tetragonal (t) stПоказать полностьюructure appears at 1276–1328 K as a first-order phase transition; the temperature and enthalpy of o-d transformation have only slight dependence on β whereas the characteristics of reversed d-o process vary greatly with cooling rate. XRD powder patterns of all samples showed no indications of a simultaneous presence of c+t domains, pointing to a single phase composition (c or t). It was suggested that the observed behavior is a consequence of two simultaneous interconnected processes of A-sublattice melting and cation/ (anion vacancy) ordering. A rarely used novel TG-DSC method based on variable gas phase composition was utilized to study properties of mobile oxygen over Sr0.8Dy0.2CoO3-δ samples. It was shown that the appearance of tetragonal phase reduces both oxygen mobility and its bonding energy, the latter decreasing substantially only at high degree of Sr2+/Dy3+ ordering. © 2020 Elsevier B.V.

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Издание

Журнал: Journal of Alloys and Compounds

Выпуск журнала: Vol. 860

Номера страниц: 158257

ISSN журнала: 09258388

Издатель: Elsevier Ltd

Персоны

  • Vereshchagin Sergei (Russian Acad Sci, Siberian Branch, Krasnoyarsk Sci Ctr, Inst Chem & Chem Technol,Fed Res Ctr, Krasnoyarsk 660036, Russia)
  • Dudnikov Vyacheslav (Russian Acad Sci, Siberian Branch, Krasnoyarsk Sci Ctr, Kirensky Inst Phys,Fed Res Ctr, Krasnoyarsk 660036, Russia)
  • Orlov Yury (Russian Acad Sci, Siberian Branch, Krasnoyarsk Sci Ctr, Kirensky Inst Phys,Fed Res Ctr, Krasnoyarsk 660036, Russia; Siberian Fed Univ, Inst Engn Phys & Radio Elect, Krasnoyarsk 660041, Russia)
  • Solovyov Leonid (Russian Acad Sci, Siberian Branch, Krasnoyarsk Sci Ctr, Inst Chem & Chem Technol,Fed Res Ctr, Krasnoyarsk 660036, Russia)