Phase diagram and crystal structure of Ti-doped HoMnO3 by high-resolution synchrotron powder diffraction
Phase diagram and crystal structure of Ti-doped HoMnO3 by high-resolution synchrotron powder diffraction
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高分辨率同步加速器粉末衍射研究 Ti 掺杂 HoMnO3 的相图和晶体结构
DOI：
10.1016/j.jssc.2022.123273
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发表时间：
2022
影响因子：
3.3
通讯作者：
Kubota Yoshiki
中科院分区：
文献类型：
--
作者：
Ishibashi Hiroki;Cubillas Fernando;Uchihashi Kento;Tsukasaki Hirofumi;Kawaguchi Shogo;Ina Toshiaki;Brown Francisco;Kimizuka Noboru;Mori Shigeo;Kubota Yoshiki
利用高角分辨、高计数统计和高空间分辨的同步辐射粉末衍射数据，研究了Ti掺杂HoMnO 3（HoMn 1-xTixO 3）的相图和详细的晶体结构。当x < 0.15时，晶体为六方晶系，空间群为P63 cm。当x ≥ 0.15时，出现了一个菱方相，其晶格常数c约为六方相的3倍。由XAFS谱估计的氧化态表明，在晶体中每个分子式单元存在x/2的过量氧。考虑到过量的氧，菱面体相的结构分析表明，晶体结构可以用中心对称空间群R3 <$c来解释。观察到了Ho原子位移的特征，这与（Mn/Ti）O层中氧原子的占位密切相关。
We investigated a phase diagram and a detailed crystal structure of Ti-doped HoMnO 3 (HoMn 1-x Ti x O 3) by synchrotron powder diffraction data with high-angular resolution and high-counting statistics as well as high-spatial resolution. For x< 0.15, it has a hexagonal structure with a space group P6 3 cm. For x≥ 0.15, a rhombohedral phase with its lattice constant c about three times larger than that of the hexagonal structure appears. Estimation of the oxidation states from XAFS spectra suggests that x/2 amount of excess oxygen per formula unit exists in crystal. Structural analysis of the rhombohedral phase, considering the excess oxygen, revealed that the crystal structure can be explained by a centrosymmetric space group R 3¯ c. Characteristic feature was observed for displacement of Ho atom, which is strongly correlated with occupancies of oxygen atoms in the (Mn/Ti) O layer.