Structure and Magnetism of Pr1−xSrxFeO3−δ

✍ Scribed by H.W. Brinks; H. Fjellvåg; A. Kjekshus; B.C. Hauback

• Publisher: Elsevier Science
• Year: 2000
• Tongue: English
• Weight: 332 KB
• Volume: 150
• Category: Article
• ISSN: 0022-4596
• DOI: 10.1006/jssc.1999.8551

✦ Synopsis

Crystal structure, redox, and magnetic properties for the Pr 1؊x Sr x FeO 3؊ solid-solution phase have been studied. Oxidized samples (prepared in air at 9003C) crystallize in the GdFeO 3type structure for 04x40.80, and probably in the Sr 8 Fe 8 O 23type (unpublished) structure for x ‫؍‬ 0.90. Reduced samples (containing virtually only Fe 3؉ ) crystallize as the perovskite aristotype for x ‫؍‬ 0.50 and 0.67 with randomly distributed vacancies. The Fe 4؉ content increases linearly in the oxidized samples up to x+0.70, whereupon it stabilizes at around 55%. Antiferromagnetic ordering of the G type is observed for oxidized samples (04x40.90) which show decreasing NeH el temperature and ordered magnetic moment with increasing x, while the NeH el temperature is nearly constant at &700 K for reduced samples. Electronic transitions for iron from an average-valence state via charge-separated to disproportionated states are proposed from anomalies in magnetic susceptibility curves in the temperature ranges 500}600 K and 150}185 K.