Competition between the Direct Exchange Interaction and Superexchange Interaction in Layered Compounds LiCrSe2, LiCrTe2, and NaCrTe2 with a Triangular Lattice

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• 作者：Shintaro Kobayashi ; Hiroaki Ueda ; Chishiro Michioka ; Kazuyoshi Yoshimura
• 刊名：Inorganic Chemistry
• 出版年：2016
• 出版时间：August 1, 2016
• 年：2016
• 卷：55
• 期：15
• 页码：7407-7413
• 全文大小：366K
• 年卷期：0
• ISSN：1520-510X

文摘

Physical properties of new S = 3/2 triangular-lattice compounds LiCrSe₂, LiCrTe₂, and NaCrTe₂ have been investigated by X-ray diffraction and magnetic measurements. These compounds crystallize in the ordered NiAs-type structure, where alkali metal ions and Cr atoms stack alternately. Despite their isomorphic structures, magnetic properties of these three compounds are different; NaCrTe₂ has an A-type spin structure with ferromagnetic layers, LiCrTe₂ is likely to exhibit a helical spin structure, and LiCrSe₂ shows a first-order-like phase transition from the paramagnetic trigonal phase to the antiferromagnetic monoclinic phase. In these compounds and the other chromium chalcogenides with a triangular lattice, we found a general relationship between the Curie–Weiss temperature and magnetic structures. This relation indicates that the competition between the antiferromagnetic direct d-d exchange interaction and the ferromagnetic superexchange interaction plays an important role in determining the ground state of chromium chalcogenides.