Sheath Bradley C, Xu Xiaoyu, Manuel Pascal, Hadermann Joke, Batuk Maria, O'Sullivan John, Bonilla Ruy S, Clarke Simon J
Department of Chemistry, University of Oxford, Inorganic Chemistry Laboratory, South Parks Road, Oxford OX1 3QR, United Kingdom.
ISIS Facility, STFC Rutherford Appleton Laboratory, Harwell Oxford, Didcot OX11 0QX, United Kingdom.
Inorg Chem. 2022 Aug 8;61(31):12373-12385. doi: 10.1021/acs.inorgchem.2c01773. Epub 2022 Jul 27.
Two novel chromium oxide arsenide materials have been synthesized, SrCrOCrOAs (i.e., SrCrAsO) and SrCrOCrAs (i.e., SrCrAsO), both of which contain chromium ions in two distinct layers. SrCrOCrOAs was targeted following electron microscopy measurements on a related phase. It crystallizes in the space group 4/ and accommodates distorted CrOAs octahedra containing Cr and distorted CrOAs octahedra containing Cr. In contrast, SrCrOCrAs incorporates Cr in CrO square-pyramidal coordination in [SrCrO] layers and Cr ions in CrAs tetrahedra in [CrAs] layers and crystallizes in the space group 4/. Powder neutron diffraction data reveal antiferromagnetic ordering in both compounds. In SrCrOCrAs the Cr moments in the [CrAs] layers exhibit long-range ordering, while the Cr moments in the [SrCrO] layers only exhibit short-range ordering. However, in SrCrOCrOAs, both the Cr moments in the CrOAs environments and the Cr moments in the CrOAs polyhedra are long-range-ordered below 530(10) K. Above this temperature, only the Cr moments are ordered with a Néel temperature slightly in excess of 600 K. A subtle structural change is evident in SrCrOCrOAs below the magnetic ordering transitions.
已经合成了两种新型氧化铬砷化物材料，即SrCrOCrOAs（即SrCrAsO）和SrCrOCrAs（即SrCrAsO），它们都在两个不同的层中含有铬离子。在对相关相进行电子显微镜测量后，将SrCrOCrOAs作为目标。它结晶于空间群4/，容纳含有Cr的扭曲CrOAs八面体和含有Cr的扭曲CrOAs八面体。相比之下，SrCrOCrAs在[SrCrO]层中以CrO四方锥配位形式包含Cr，在[CrAs]层中以CrAs四面体形式包含Cr离子，并结晶于空间群4/。粉末中子衍射数据揭示了这两种化合物中的反铁磁有序。在SrCrOCrAs中，[CrAs]层中的Cr磁矩表现出长程有序，而[SrCrO]层中的Cr磁矩仅表现出短程有序。然而，在SrCrOCrOAs中，CrOAs环境中的Cr磁矩和CrOAs多面体中的Cr磁矩在530(10)K以下都是长程有序的。高于此温度，只有Cr磁矩有序，奈尔温度略高于600K。在磁性有序转变温度以下，SrCrOCrOAs中明显存在细微的结构变化。
