The crystal structures and physical properties of the solid solution compound Ba<sub>5</sub>Y<sub>8-x</sub>Mn<sub>4</sub>O<sub>21-1.5x</sub>（x = 0,1） |
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| Authors: | Gao Qing-Qing Li Jing-Bo Song Shi-Jia Rao Guang-Hui Luo Jun Liu GuangYao and Liang Jing-Kui |
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| Affiliation: | Beijing National Laboratory for Condensed Matter Physics,Institute of Physics,Chinese Academy of Sciences |
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| Abstract: | New oxometallides with the formula Ba5Y8 xMn4O21 1.5x(x = 0,1) are prepared through an atmospherecontrolled solid-state reaction.Two single-phase samples with Ba/Y/Mn atomic ratios 5/8/4(Y8) and 5/7/4(Y7) are obtained.The crystal structures and the physical properties of the compounds are investigated by X-ray powder diffraction,magnetization,conductivity,and dielectricity measurements.The Ba5Y8 xMn4O21 1.5x compound is demonstrated to be a Y-deficient solid solution.The solid solution compound Ba5Y8 xMn4O21 1.5x crystallizes into tetragonal symmetry with the space group I4/m.Detailed structure analysis by Rietveld refinement of the X-ray powder diffraction data reveals that the Y vacancies occur preferentially at the Y(2) site.Thermal magnetization measurements indicate the presence of antiferromagnetic interaction between Mn ions in the compounds,and temperature-dependent resistivity measurements show that insulator-semiconductor transitions occur around 175 K and 170 K for the Y8 and Y7 samples,respectively.Strong frequency dependences of the dielectric constant are observed above ～175 K for the two compounds. |
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| Keywords: | Ba5Y8 xMn4O21 1 5x X-ray powder diffraction crystal structure conductivity |
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