Selective substitution of vanadium for molybdenum in Sr2(Fe1−xVx)MoO6 double perovskites |
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Authors: | Q Zhang Q Huang ZW Ouyang BH Toby |
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Institution: | a Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080, People's Republic of China b NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD 20899-8562, USA c Institute of Materials Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, People's Republic of China |
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Abstract: | The crystal and magnetic structures of Sr2(Fe1−xVx)MoO6 (0.03?x?0.1) compounds are refined by alternately using X-ray powder diffraction (XRD) and neutron powder diffraction (NPD) data collected at room temperature. The refinement results reveal that the V atoms selectively occupy the Mo sites instead of the Fe sites for x?0.1. The 3d/4d cation ordering decreases with the increase of the V content. Slight distortions in the lattice and metal octahedra are shown at 300 K, and the distortions increase at 4 K. The magnetic structure at 4 K can be modeled equally well with the moments aligning along 001], 110] or 111] directions. The total moments derived from the NPD data for the 110] and 111] direction models agree well with the magnetic measurements, whereas the 001] model leads to a smaller total moment. Bond valence analysis indicates that Sr ions are properly located in the structure and Mo ions are compatible with both the Fe sites and the Mo sites. The electronic effects are suggested to be responsible for the selective occupation of the V on the Mo sites due to the different distortions of the FeO6 and MoO6 octahedra. |
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Keywords: | Crystal and magnetic structures Preferential site occupation Neutron powder diffraction Double perovskites |
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