Abstract
The non-stoicheiometric phase SrCoO3–Y has been studied by Mössbauer spectroscopy using 57Fe as an impurity probe, and by X-ray powder diffraction. The fully reduced phase Sr2Co2O5 contains high-spin Co3+ in both octahedral and tetrahedral sites, and has the same magnetic spin arrangement as the analogous iron compound. Oxidation produces a poorly defined ‘hexagonal’ phase which is apparently non-magnetic even at 4.2 K. There is evidence to suggest that the structure of this phase is related to that of the brownmillerite lattice with the retention of layers of tetrahedrally co-ordinated Co3+, but with a high-spin to low-spin transition occurring on the octahedral sites. Slow relaxation effects have been observed for the iron impurities at low temperature, including a novel slow relaxation for Fe4+ ions.

This publication has 0 references indexed in Scilit: