Structural Properties, Mössbauer Spectra, and Magnetism of Perovskite-Type Oxides SrFe1–xTixO3–y

✍ Scribed by Peter Adler; Sten Eriksson

• Publisher: John Wiley and Sons
• Year: 2000
• Tongue: German
• Weight: 132 KB
• Volume: 626
• Category: Article
• ISSN: 0372-7874
• DOI: 10.1002/(sici)1521-3749(200001)626:1<118::aid-zaac118>3.0.co;2-k

✦ Synopsis

Perovskite-type phases SrFe 1±x Ti x O 3±y with 0.1 £ x £ 0.7 have been prepared from the oxides, and, in order to reach high oxygen contents and Fe IV fractions, annealed at oxygen pressures of 60 MPa. The materials were characterised by powder x-ray and neutron diffraction, 57 Fe Mo È ssbauer spectroscopy, and magnetic susceptibility measurements. All samples of the series crystallise in a cubic perovskite structure and reveal considerable oxygen deficiency. The Mo È ssbauer parameters suggest that for x = 0.1, where the Fe IV fraction is about 90%, the itinerant electronic state of SrFeO 3 is essentially retained. In materials with larger x increasing amounts of Ti IV and Fe III ions lead to a stronger localisation of the r* (Fe 3 d ± O 2 p) electrons. There is no evidence for a charge disproportionation of Fe IV in any of the materials. Magnetic susceptibility measurements show a divergence of zero-field cooled and field-cooled data below a temperature T m and deviations from Curie-Weiss behaviour above T m . The data are indicative of spin-glass behaviour due to disorder and competing exchange interactions.