Crystal Growth and Phase Formation of High-Entropy Rare-Earth Aluminum Perovskites
Crystal Growth and Phase Formation of High-Entropy Rare-Earth Aluminum Perovskites
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DOI：
10.1021/acs.cgd.2c01130
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发表时间：
2022-12
期刊：
影响因子：
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通讯作者：
Matheus Pianassola;B. Chakoumakos;C. Melcher;M. Zhuravleva
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作者：
Matheus Pianassola;B. Chakoumakos;C. Melcher;M. Zhuravleva
我们首次展示了用微下拉方法生长高熵稀土铝钙钛矿(REAlO_3)的晶体，为未来功能晶体的开发提供了参考。为了确定组成如何影响相形成，我们从下面的列表中制定了包含五个Re的等原子组成：Lu，Yb，Tm，Er，Y，Ho，Dy，Tb，Gd，Eu，Sm，Nd，Pr，Ce，La。为了测试具有相似离子半径的RE的组合是否有利于单一相，配制了包含具有连续或不连续离子半径值的RE的组合物。粉末和单晶X-射线衍射谱表明，只有离子半径相近的Re形成正交单稀土REAlO_3的晶体是单相。含有具有不同离子半径的Re的晶体或形成正交、菱形和四方单晶RE-REAlO_3的RE的混合物是相的混合物。通过电子探针显微分析单相晶体中的元素分布，证实没有证据表明有任何RE组分的优先掺入。用扫描电子显微镜和能谱分析了第二相的分布和组成，认为第二相是晶体中心的一个小区域，具有靠近外表面的分枝特征。
We demonstrate for the first time the crystal growth of high-entropy rare-earth (RE) aluminum perovskites (REAlO3) using the micro-pulling-down method to inform future exploration of functional crystals. To determine how composition affects phase formation, we formulate equiatomic compositions containing five REs from the following list: Lu, Yb, Tm, Er, Y, Ho, Dy, Tb, Gd, Eu, Sm, Nd, Pr, Ce, La. To test whether combinations of REs with similar ionic radii may favor a single phase, compositions containing REs with consecutive or nonconsecutive ionic radius values were formulated. Powder and single-crystal X-ray diffraction indicate that crystals containing only REs with similar ionic radii that form orthorhombic single-RE REAlO3are a single phase. Crystals containing REs with dissimilar ionic radii or mixtures of REs that form orthorhombic, rhombohedral, and tetragonal single-RE REAlO3are a mixture of phases. The elemental distribution in single-phase crystals analyzed via electron probe microanalysis confirms no evidence of preferential incorporation of any of the constituent REs. The distribution and composition of secondary phases were analyzed via scanning electron microscopy and energy dispersive spectroscopy; secondary phases were seen as a small region in the center of the crystals with branching features closer to the outer surface.