Crystal structure and electrical properties of the pyrochlore ruthenate Bi[sub 2-x]Y[sub x]Ru[sub 2]O[sub 7]

Journal Article · Fri Jan 01 04:00:00 EST 1993 · Journal of Solid State Chemistry; (United States)

DOI:https://doi.org/10.1006/jssc.1993.1012· OSTI ID:7078615

Kanno, R; Takeda, Y; Yamamoto, T; Kawamoto, Y; Yamamoto, O ^[1]

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1. Kobe Univ. (Japan) Miew Univ., Tsu (Japan)

The bismuth yttrium pyrochlore ruthenates Bi[sub 2-x]Y[sub x]Ru[sub 2]O[sub 7] have been synthesized and characterized by x-ray Rietveld structure refinement and electrical conductivity measurement. Room temperature resistivities increase with x, and a change from metallic to semiconducting behavior is observed between x = 1.2 and 1.4. The distortion of the RuO[sub 6] octahedra and the bend in the RuO[sub 6] zig-zag chains increase with x. The transition from metallic to semiconducting state is correlated with the variation of the Ru-O-Ru angle from 139[degree] at x = 0.0 to 129[degree] at x = 2.0. The Ru-O bond length in the RuO[sub 6] octahedra increases in the interval O [le] x [le] 1.2. This variation is understood to result from the contribution of Bi orbitals to the conduction band; in the metallic regime, O [le] x [le] 1.2, the electron transfer leads to short Ru-O bond length, whereas in the nonmetallic state there is little Ru-O bond length variation because there is no contribution of the Bi electrons to the Ru 4d state.

• OSTI ID: 7078615
• Journal Information: Journal of Solid State Chemistry; (United States), Journal Name: Journal of Solid State Chemistry; (United States) Vol. 102:1; ISSN 0022-4596; ISSN JSSCBI
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360202 -- Ceramics
Cermets
& Refractories-- Structure & Phase Studies
360204* -- Ceramics
Cermets
& Refractories-- Physical Properties
BISMUTH COMPOUNDS
BISMUTH OXIDES
CHALCOGENIDES
CRYSTAL STRUCTURE
ELECTRICAL PROPERTIES
MATERIALS
MINERALS
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
PYROCHLORE
REFRACTORY METAL COMPOUNDS
RUTHENIUM COMPOUNDS
RUTHENIUM OXIDES
SEMICONDUCTOR MATERIALS
TRANSITION ELEMENT COMPOUNDS
YTTRIUM COMPOUNDS
YTTRIUM OXIDES