Orbital Arrangements and Magnetic Interactions in the Quasi-One-Dimensional Cuprates ACuMoO4(OH) (A = Na, K)

• Published in: Inorganic chemistry Vol. 54; no. 11; pp. 5566 - 5570
• Main Authors: Nawa, Kazuhiro, Yajima, Takeshi, Okamoto, Yoshihiko, Hiroi, Zenji
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 01.06.2015
• ISSN: 0020-1669; 1520-510X
• DOI: 10.1021/acs.inorgchem.5b00686

A new spin-1/2 quasi-one-dimensional antiferromagnet KCuMoO4(OH) is prepared by the hydrothermal method. The crystal structures of KCuMoO4(OH) and the already-known Na-analogue NaCuMoO4(OH) are isotypic, comprising chains of Cu2+ ions in edge-sharing CuO4(OH)2 octahedra. Despite the structural similarity, their magnetic properties are quite different because of the different arrangements of d x 2 –y 2 orbitals carrying spins. For NaCuMoO4(OH), d x 2 –y 2 orbitals are linked by superexchange couplings via two bridging oxide ions, which gives a ferromagnetic nearest-neighbor interaction J 1 of −51 K and an antiferromagnetic next-nearest-neighbor interaction J 2 of 36 K in the chain. In contrast, a staggered d x 2 –y 2 orbital arrangement in KCuMoO4(OH) results in superexchange couplings via only one bridging oxide ion, which makes J 1 antiferromagnetic as large as 238 K and J 2 negligible. This comparison between the two isotypic compounds demonstrates an important role of orbital arrangements in determining the magnetic properties of cuprates.