Simpson Struan, Milton Michael, Fop Sacha, Stenning Gavin B G, Hopper Harriet Alexandra, Ritter Clemens, Mclaughlin Abbie C
Chemistry Department, University of Aberdeen, Meston Walk, Aberdeen AB24 3UE, U.K.
ISIS Experimental Operations Division, Rutherford Appleton Laboratory, Harwell Science and Innovation Campus, Didcot OX11 0QX, U.K.
Inorg Chem. 2022 Aug 1;61(30):11622-11628. doi: 10.1021/acs.inorgchem.2c01102. Epub 2022 Jul 19.
Extended solid-state materials based on the hexagonal perovskite framework are typified by close competition between localized magnetic interactions and quasi-molecular electronic states. Here, we report the structural and magnetic properties of the new six-layer hexagonal perovskite BaCaMoO. Neutron diffraction experiments, combined with magnetic susceptibility measurements, show that the MoO dimers retain localized character down to 5 K and adopt nonmagnetic spin-singlet ground states. This is in contrast to the recently reported BaSrMoO analogue, in which the MoO dimers spontaneously separate into a mixture of localized and quasi-molecular ground states. Structural distortions in both BaCaMoO and BaSrMoO have been studied with the aid of distortion mode analyses to elucidate the coupling between the crystal lattice and electronic interactions in 6H Mo hexagonal perovskites.
基于六方钙钛矿框架的扩展固态材料的特点是局域磁相互作用和准分子电子态之间存在紧密竞争。在此，我们报告了新型六层六方钙钛矿BaCaMoO的结构和磁性。中子衍射实验结合磁化率测量表明，MoO二聚体在低至5 K时仍保持局域特性，并采用非磁性自旋单重态基态。这与最近报道的BaSrMoO类似物形成对比，在BaSrMoO中，MoO二聚体自发分离为局域基态和准分子基态的混合物。借助畸变模式分析研究了BaCaMoO和BaSrMoO中的结构畸变，以阐明6H Mo六方钙钛矿中晶格与电子相互作用之间的耦合。
