Crystal structure and monoclinic distortion of glaserite-type Ba3MnSi2O8
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Date
2018-10-01
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Elsevier
Abstract
Crystal structure and magnetic properties of glaserite-type Ba3MnSi2O8 were investigated using variable temperature neutron powder diffraction and magnetometry. At room temperature the composition is hexagonal and the crystal structure is best described by the P-3m1 space group (a~ 5.7 Å, c~ 7.3 Å) with the apical oxygen atom modelled on a split site. On cooling below ~ 250 K the structure undergoes a phase transition into a monoclinic C2/c form (√3ahex, ahex, 2chex, β~ 90°). Analysing diffraction data in terms of symmetry-adapted distortion modes suggests that the transition is primarily driven by increasing in-plane displacements of O1, which in turn results in the coupled tilting of [SiO4] and [MnO6] octahedra and in-plane displacements of Ba1 atoms. Magnetic susceptibility measurements and neutron powder diffraction data show no evidence for long-range magnetic ordering down to 1.6 K, although the development of magnetic diffuse scattering suggests that a magnetic transition may take place at lower temperature. Crown Copyright © 2018 Published by Elsevier Inc.
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Keywords
Crystal structure, Phase transformations, Neutron diffraction, Monoclinic lattices, Magnetic susceptibility, Magnetic properties
Citation
Avdeev, M., Xia, Q., Sale, M., Allison, M., & Ling, C. D. (2018). Crystal structure and monoclinic distortion of glaserite-type Ba3MnSi2O8. Journal of Solid State Chemistry, 266, 1-8, doi:10.1016/j.jssc.2018.07.001