Le cobaltite de strontium Sr2Co2O5 : Caracterisation et proprietes magnetiques
1979; Elsevier BV; Volume: 14; Issue: 6 Linguagem: Inglês
10.1016/0025-5408(79)90145-4
ISSN1873-4227
AutoresJean‐Claude Grenier, Samir Ghodbane, G. Demazeau, Michel Pouchard, Paul Hagenmuller,
Tópico(s)Iron-based superconductors research
ResumoStoichiometric strontium cobaltite oxide Sr2Co2O5 has been prepared at 910°C in air and characterized by chemical analysis and X-ray diffraction. Temperature dependent magnetic measurements have shown a magnetic transition which is confirmed by DTA and related to a structural modification. At high temperature a brownmillerite-type structure is stabilized by the high spin state of the trivalent cobalt (four free electrons). On the other hand, the magnetic behaviour of the low temperature phase which derives from the 2H-perovskite type may be explained by the simultaneous presence of an intermediary spin state (two free electrons) and a low spin state (no free electron) of trivalent cobalt. These electronic transitions are discussed in connection with the cobalt environment.
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