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arXiv · 1505.05332

Orbital Arrangements and Magnetic Interactions in the Quasi-One-Dimensional Cuprates ACuMoO_4(OH) (A = Na, K)

Kazuhiro Nawa·Takeshi Yajima·Yoshihiko Okamoto·Zenji Hiroi
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Abstract

A new spin-1/2 quasi-one-dimensional antiferromagnet KCuMoO_4(OH) is prepared by the hydrothermal method. The crystal structures of KCuMoO_4(OH) and the already-known Na-analogue, NaCuMoO_4(OH), are isotypic, comprising chains of Cu^{2+} ions in edge-sharing CuO_4(OH)_2 octahedra. Despite the structural similarity, their magnetic properties are quite different because of the different arrangements of d_{x2-y2} orbitals carrying spins. For NaCuMoO_4(OH), d_{x2-y2} 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_{x2-y2} orbital arrangement in KCuMoO_4(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.

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Kazuhiro Nawa, Takeshi Yajima, Yoshihiko Okamoto, Zenji Hiroi. 2015-05-20. Orbital Arrangements and Magnetic Interactions in the Quasi-One-Dimensional Cuprates ACuMoO_4(OH) (A = Na, K). https://doi.org/10.1021/acs.inorgchem.5b00686

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