The Ising triangular lattice remains the classic test-case for frustrated magnetism. Here we report neutron scattering measurements of short range magnetic order in CuMnO2, which consists of a distorted lattice of Mn3+ spins with single-ion anisotropy. Physical property measurements on CuMnO2 are consistent with 1D correlations caused by anisotropic orbital occupation. However the diffuse magnetic neutron scattering seen in powder measurements has previously been fitted by 2D Warren-type correlations. Using neutron spectroscopy, we show that paramagnetic fluctuations persist up to ∼25 meV above TN= 65 K. This is comparable to the incident energy of typical diffractometers, and results in a smearing of the energy integrated signal, which hence cannot be analysed in the quasi-static approximation. We use low energy XYZ polarised neutron scattering to extract the purely magnetic (quasi)-static signal. This is fitted by reverse Monte Carlo analysis, which reveals that two directions in the triangular layers are perfectly frustrated in the classical spin-liquid phase at 75 K. Strong antiferromagnetic correlations are only found along the b-axis, and our results hence unify the pictures seen by neutron scattering and macroscopic physical property measurements.

中文翻译：

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受挫三角晶格材料CuMnO ₂中的自旋链相关性

Ising 三角形晶格仍然是受挫磁力的经典测试案例。在这里，我们报告了 CuMnO2 中短程磁序的中子散射测量，它由具有单离子各向异性的 Mn3+ 自旋的扭曲晶格组成。CuMnO2 的物理性质测量与由各向异性轨道占据引起的一维相关性一致。然而，在粉末测量中看到的漫磁中子散射以前已经通过 2D Warren 型相关性拟合。使用中子光谱，我们表明顺磁波动在 TN = 65 K 以上持续高达 ~25 meV。这与典型衍射仪的入射能量相当，并导致能量积分信号的模糊，因此无法在准静态近似。我们使用低能量 XYZ 极化中子散射来提取纯磁（准）静态信号。这是通过反向蒙特卡罗分析拟合的，它表明三角形层中的两个方向在 75 K 的经典自旋液相中完全受挫。仅沿 b 轴发现强反铁磁相关性，因此我们的结果统一了通过中子散射和宏观物理性质测量看到的图片。