Oxygen nonstoichiometry and magnetotransport properties of Sr 2(Y1-xCax)Co2O7+δ cobalt oxides

M. Matvejeff, J. Nakamura, H. Yamauchi, M. Karppinen*

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

1 Citation (Scopus)

Abstract

Tunability of oxygen nonstoichiometry of the Co-based Ruddlesden-Popper phase, Sr2(Y1-xCax)Co2O 7+δ, has been investigated using single-phase samples obtained by means of solid-state synthesis within 0.3≤x≤0.5. With cerimetric titrations and thermogravimetric measurements carried out in O2 and Ar atmospheres, it is found that wide-range oxygen tuning is possible over the whole range of cation stoichiometry, 0.3≤x≤0.5. The minimum oxygen content corresponds to δ≈-1.2 for all the samples (with 0.3≤x≤0.5), while the maximum amount of oxygen loaded in the structure upon 1atm O 2 annealing increases as x decreases, reaching δ=-0.52 at x=0.3. The change in oxygen nonstoichiometry is reflected in the magnetic and magnetotransport properties of the phase. A small magnetoresistance effect (up to ∼3.5%) is revealed for the oxygenated samples at low temperatures.

Original languageEnglish
Pages (from-to)329-333
Number of pages5
JournalMaterials Chemistry and Physics
Volume85
Issue number2-3
DOIs
Publication statusPublished - 15 Jun 2004
MoE publication typeA1 Journal article-refereed

Keywords

  • Chemical analysis
  • Magnetoresistance
  • Oxygen nonstoichiometry
  • Ruddlesden-Popper phase

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