Oxygen and cation ordered perovskite, Ba2Y2Mn 4O11

M. Karppinen*, H. Okamoto, H. Fjellvåg, T. Motohashi, H. Yamauchi

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

36 Citations (Scopus)

Abstract

A three-step route has been developed for the synthesis of a new oxygen-ordered double perovskite, BaYMn2O5.5 or Ba 2Y2Mn4O11. (i) The A-site cation ordered perovskite, BaYMn2O5+δ, is first synthesized at δ≈0 by an oxygen-getter-controlled low-O2-pressure encapsulation technique utilizing FeO as the getter for excess oxygen. (ii) The as-synthesized, oxygen-deficient BaYMn2O5.0 phase is then readily oxygenated to the δ≈1 level by means of 1-atm-O2 annealing at low temperatures. (iii) By annealing this fully oxygenated BaYMn2O6.0 in flowing N2 gas at moderate temperatures the new intermediate oxygen content oxide, BaYMn2O 5.5 or Ba2Y2Mn4O11, is finally obtained. From thermogravimetric observation it is seen that the final oxygen depletion from δ≈1.0 to 0.5 occurs in a single sharp step about 600°C, implying that the oxygen stoichiometry of BaYMn2O 5+δ is not continuously tunable within 0.5<δ<1.0. For BaYMn2O5.5 synchrotron X-ray diffraction analysis reveals an orthorhombic crystal lattice and a long-range ordering of the excess oxygen atoms in the YO0.5 layer. The magnetic behavior of BaYMn 2O5.5 (with a ferromagnetic transition at ∼133K) is found different from those previously reported for the known phases, BaYMn 2O5.0 and BaYMn2O6.0.

Original languageEnglish
Pages (from-to)2122-2128
Number of pages7
JournalJournal of Solid State Chemistry
Volume177
Issue number6
DOIs
Publication statusPublished - Jun 2004
MoE publication typeA1 Journal article-refereed

Keywords

  • Encapsulation synthesis
  • FeO oxygen getter
  • Mn-based double-perovskite
  • Oxygen ordering
  • Oxygen stoichiometry
  • Thermogravimetry

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