Crystal structures and magnetic properties of 6H-perovskite-type oxides Ba{sub 3}MIr{sub 2}O{sub 9} (M=Mg, Ca, Sc, Ti, Zn, Sr, Zr, Cd and In)
- Division of Chemistry, Graduate School of Science, Hokkaido University, Sapporo 060-0810 (Japan)
Crystal structures and magnetic properties of quaternary oxides Ba{sub 3}MIr{sub 2}O{sub 9} (M=Mg, Ca, Sc, Ti, Zn, Sr, Zr, Cd and In) were investigated. Rietveld analyses of their X-ray diffraction data indicate that they adopt the 6H-perovskite-type structure with space group P6{sub 3}/mmc or, in the case of M=Ca, Sr and Cd, a monoclinically distorted structure with space group C2/c. The Ir valence configurations are Ba{sub 3}M{sup 2+}Ir{sub 2}{sup 5+}O{sub 9} (M=Mg, Ca, Zn, Sr and Cd), Ba{sub 3}M{sup 3+}Ir{sub 2}{sup 4.5+}O{sub 9} (M=Sc and In) and Ba{sub 3}M{sup 4+}Ir{sub 2}{sup 4+}O{sub 9} (M=Ti and Zr). Magnetic susceptibility and specific heat measurements were carried out. In the Ba{sub 3}M{sup 2+}Ir{sub 2}{sup 5+}O{sub 9}, the Ir{sup 5+} ions have a non-magnetic ground state and the magnetic behavior for these compounds is explained by the Kotani's theory. For Ba{sub 3}M{sup 4+}Ir{sub 2}{sup 4+}O{sub 9}, the effective magnetic moment of these compounds is significantly small, although the Ir{sup 4+} ions have magnetic moment, which indicates the existence of the strong antiferromagnetic interaction between Ir{sup 4+} ions in the Ir{sup 4+}{sub 2}O{sub 9} face-shared bioctahedra. In the case of Ba{sub 3}M{sup 3+}Ir{sub 2}{sup 4.5+}O{sub 9}, a specific heat anomaly was found at about 10K (M=Sc) and 1.6K (M=In), which suggests the magnetic ordering of the magnetic moments of Ir{sup 4+} in the (Ir{sup 4+}Ir{sup 5+})O{sub 9} bioctahedra.
- OSTI ID:
- 20905414
- Journal Information:
- Journal of Solid State Chemistry, Vol. 179, Issue 8; Other Information: DOI: 10.1016/j.jssc.2006.04.055; PII: S0022-4596(06)00222-2; Copyright (c) 2006 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); ISSN 0022-4596
- Country of Publication:
- United States
- Language:
- English
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