Crystal structure and dielectric properties of ordered perovskites Ba2BiSbO6 and BaSrBiSbO6 |
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Authors: | RVK Mangalam A Sundaresan |
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Institution: | a Chemistry and Physics of Materials Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur P.O., Bangalore 560064, India b Institut Laue Langevin, 6, Rue Jules Horowitz, 38042 Grenoble Cedex 9, France |
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Abstract: | Neutron powder diffraction studies showed that the ordered perovskites Ba2BiSbO6 (BBS) and BaSrBiSbO6 (BSBS) crystallize in a rhombohedral structure with the space group R3¯. The room-temperature lattice parameters are a=6.0351(2) Å; α=60.202(1)° and a=5.9809(2) Å; α=60.045(2)°, respectively. BBS exhibits a dielectric anomaly near room temperature which may be related to structural transition from the R3¯ to low-temperature monoclinic I2/m symmetry. BSBS shows a dielectric anomaly near 723 K which coincides with a phase transition from the rhombohedral to cubic (Fm3¯m) structure. In contrast to BBS, BSBS does not undergo structural transition below room temperature. |
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Keywords: | 61 50 Ks 61 05 fm 77 22 &minus d |
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