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arXiv 0907.0742cond-mat.str-elcond-mat.mtrl-sci
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自旋为2的α- NaMnO2三角晶格中的一维磁涨落

One-dimensional magnetic fluctuations in the spin-2 triangular lattice α-NaMnO2

C. Stock, L. C. Chapon, O. Adamopoulos, A. Lappas, M. Giot, J. W. Taylor, M. A. Green, C. M. Brown, P. G. Radaelli

摘要:

用中子非弹性散射研究了S=2各向异性三角形点阵α-NaMnO_2。在T ~ 45 K出现反铁磁有序,自旋能隙打开.用单模近似分析了能隙以上磁动力学的谱权(Δ ~ 7.5 meV)。当考虑沿单斜b轴的主要交换相互作用(|J| /k_B ~ 73 K)和相当大的易轴磁各向异性(|D| /k_B ~ 3 K)时,计算结果与实验符合得很好.尽管早期的二维自旋相互作用的建议,动力学说明强耦合反铁磁S=2链和取消链间交换由于晶格拓扑结构。因此,α-NaMnO 2代表了一个模型系统,其中通过降低自旋相互作用的维数来解决几何挫折。

英文摘要:

The S=2 anisotropic triangular lattice alpha-NaMnO2 is studied by neutron inelastic scattering. Antiferromagnetic order occurs at T ~ 45 K with opening of a spin gap. The spectral weight of the magnetic dynamics above the gap (Delta ~ 7.5 meV) has been analysed by the single-mode approximation. Excellent agreement with the experiment is achieved when a dominant exchange interaction (|J|/k_B ~ 73 K), along the monoclinic b-axis and a sizeable easy-axis magnetic anisotropy (|D|/k_B ~ 3 K) are considered. Despite earlier suggestions for two-dimensional spin interactions, the dynamics illustrate strongly coupled antiferromagnetic S=2 chains and cancellation of the interchain exchange due to the lattice topology. alpha-NaMnO2 therefore represents a model system where the geometric frustration is resolved through the lowering of the dimensionality of the spin interactions.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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