Mustonen O, Vasala S, Sadrollahi E, Schmidt K P, Baines C, Walker H C, Terasaki I, Litterst F J, Baggio-Saitovitch E, Karppinen M
Department of Chemistry and Materials Science, Aalto University, FI-00076, Espoo, Finland.
Centro Brasileiro de Pesquisas Físicas (CBPF), Rua Dr Xavier Sigaud 150, Urca, Rio de Janeiro, 22290-180, Brazil.
Nat Commun. 2018 Mar 14;9(1):1085. doi: 10.1038/s41467-018-03435-1.
A quantum spin liquid state has long been predicted to arise in spin-1/2 Heisenberg square-lattice antiferromagnets at the boundary region between Néel (nearest-neighbor interaction dominates) and columnar (next-nearest-neighbor interaction dominates) antiferromagnetic order. However, there are no known compounds in this region. Here we use d-d cation mixing to tune the magnetic interactions on the square lattice while simultaneously introducing disorder. We find spin-liquid-like behavior in the double perovskite SrCu(TeW)O, where the isostructural end phases SrCuTeO and SrCuWO are Néel and columnar type antiferromagnets, respectively. We show that magnetism in SrCu(TeW)O is entirely dynamic down to 19 mK. Additionally, we observe at low temperatures for SrCu(TeW)O-similar to several spin liquid candidates-a plateau in muon spin relaxation rate and a strong T-linear dependence in specific heat. Our observations for SrCu(TeW)O highlight the role of disorder in addition to magnetic frustration in spin liquid physics.
长期以来，人们一直预测在自旋为1/2的海森堡正方晶格反铁磁体中，在奈尔（最近邻相互作用占主导）和柱状（次近邻相互作用占主导）反铁磁序之间的边界区域会出现量子自旋液体态。然而，在这个区域没有已知的化合物。在这里，我们利用d-d阳离子混合来调节正方晶格上的磁相互作用，同时引入无序。我们在双钙钛矿SrCu(TeW)O中发现了类似自旋液体的行为，其中同构的端相SrCuTeO和SrCuWO分别是奈尔型和柱状型反铁磁体。我们表明，SrCu(TeW)O中的磁性在低至19 mK时完全是动态的。此外，我们在低温下观察到SrCu(TeW)O——类似于几种自旋液体候选物——μ子自旋弛豫率出现平台，并且比热具有强烈的T线性依赖性。我们对SrCu(TeW)O的观察突出了无序在自旋液体物理学中除了磁阻挫之外的作用。
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