Structure and properties of antimony-doped lanthanum molybdate La{sub 2}Mo{sub 2}O{sub 9}

Journal Article · Sun May 15 04:00:00 EDT 2011 · Crystallography Reports

DOI:https://doi.org/10.1134/S1063774511020039· OSTI ID:22054287

Verin, I A; Sorokina, N I ^[1]; Kharitonova, E P; Voronkova, V I ^[2]

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1. Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation)
2. Moscow State University (Russian Federation)

Polycrystalline samples of the composition La{sub 2}Mo{sub 2-x}Sb{sub x}O{sub 9-y}, where 0 {<=} x {<=} 0.05, were prepared by solid-phase synthesis. Single crystals of La{sub 2}Mo{sub 1.96}Sb{sub 0.04}O{sub 8.17} were obtained by spontaneous crystallization from flux. The structure of the metastable {beta}{sub ms} phase of this compound was determined at room temperature by X-ray diffraction. It was found that the La, Mo, and O1 atoms are displaced from the threefold axis on which they are located in the high-temperature {beta} phase. It was shown that molybdenum atoms in the crystal structure are partially replaced by antimony atoms, which are located on the threefold axis. In antimony-doped crystals, lanthanum atoms partially return to the site on the threefold axis and the coordination environment of molybdenum cations becomes more ordered, thus facilitating the stabilization of the cubic phase at room temperature. Calorimetric measurements (DSC) showed that the introduction of Sb as the dopant into the La{sub 2}Mo{sub 2}O{sub 9} structure leads to a decrease in the temperature of the {alpha} {yields} {beta} phase transition from 570 to 520 Degree-Sign C and to the partial suppression of this transition. The temperature behavior of the conductivity confirms the DSC data. Thus, doping with Sb contributes to the stabilization of the cubic phase at room temperature.

• OSTI ID: 22054287
• Journal Information: Crystallography Reports, Journal Name: Crystallography Reports Journal Issue: 3 Vol. 56; ISSN 1063-7745; ISSN CYSTE3
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ANTIMONY
CALORIMETRY
CRYSTAL STRUCTURE
CRYSTALLIZATION
DOPED MATERIALS
LANTHANUM COMPOUNDS
MOLYBDATES
MONOCRYSTALS
POLYCRYSTALS
SOLIDS
STABILIZATION
SYNTHESIS
TEMPERATURE RANGE 0273-0400 K
X-RAY DIFFRACTION