Neutron scattering sum rules, symmetric exchanges, and helicoidal magnetism in MnSb 2 O 6
Neutron scattering sum rules, symmetric exchanges, and helicoidal magnetism in MnSb 2 O 6
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MnSb 2 O 6 中的中子散射和规则、对称交换和螺旋磁性
DOI：
10.1103/physrevb.107.144420
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发表时间：
2023
影响因子：
3.7
通讯作者：
Chan E
中科院分区：
文献类型：
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作者：
Chan E
是基于非质心空间群，磁自旋在摆线结构中有序。自旋旋转平面被发现是倾斜远离轴[Kinoshita，物理评论Lett。117，047201（2016）10.1103/PhysRevLett.117.047201]，从而产生螺旋基态，我们称之为倾斜结构。在我们之前的衍射研究[Chan，Phys. Rev. B 106，064403（2022）10.1103/PhysRevB.106.064403]中，我们没有发现这种倾斜结构优于纯摆线级（称为非倾斜结构）的证据。基态磁结构，预计将建立和起源于七个最近的邻居海森堡交换常数，已被证明是耦合到潜在的晶体手性与极性域切换正在报道。我们应用中子能谱提取这些对称交换常数。鉴于磁交换网络的高度复杂性，晶体结构和复杂性拟合许多参数的线性自旋波模型，我们利用多路复用中子仪器使用的第一时刻和规则的中子散射来估计这些对称交换常数。中子散射的一阶矩提供了一种方法，如果两个有序自旋的相对角度和距离已知，则可以推导出两个相邻自旋之间的海森堡交换常数。我们表明，第一时刻总和规则结合已知的磁有序波矢固定的7个交换常数中的6个。由于不同手性交换相互作用存在相等的空间键距，因此该分析不能确定剩余的交换常数。然而，我们发现这个参数是固定的磁区边界附近的磁振子色散，这是不敏感的全球磁结构的倾斜。然后，我们使用这些参数来计算Néel态的低能自旋波，以再现没有强反对称耦合的中子响应。使用绿色的响应函数，长波长激发的稳定性，然后在我们提出的非倾斜磁结构的背景下进行了讨论。结果表明，存在强对称的交换常数的手性交换途径，并说明了一个潜在的耦合晶体和磁性的“手性”，通过占主导地位的对称交换。我们进一步认为，激发可以一致地建模在一个untightened的磁结构中的存在下，仅交换常数。
is based on the noncentrosymmetricspace group with magnetic(,) spins ordering belowin a cycloidal structure. The spin rotation plane was found to be tilted away from theaxis [Kinoshita , Phys. Rev. Lett. 117, 047201 (2016)10.1103/PhysRevLett.117.047201] resulting as a helicoidal ground state, which we refer as the tilted structure. In our previous diffraction study [Chan , Phys. Rev. B 106, 064403 (2022)10.1103/PhysRevB.106.064403] we found no evidence that this tilted structure is favored over the pure cycloidal order (referred as the untilted structure). The ground-state magnetic structure, expected to be built and originate from seven nearest-neighbor Heisenberg exchange constants, has been shown to be coupled to the underlying crystallographic chirality with polar domain switching being reported. We apply neutron spectroscopy to extract these symmetric exchange constants. Given the high complexity of the magnetic exchange network, crystallographic structure and complications fitting many parameter linear spin-wave models, we take advantage of multiplexed neutron instrumentation to use the first moment sum rule of neutron scattering to estimate these symmetric exchange constants. The first moment of neutron scattering provides a way of deriving the Heisenberg exchange constant between two neighboring spins if the relative angle and distance of the two ordered spins is known. We show that the first moment sum rule combined with the known magnetic ordering wavevector fixes six of the seven exchange constants. The remaining exchange constant is not determined by this analysis because of the equal spatial bond distances present for different chiral exchange interactions. However, we find this parameter is fixed by the magnon dispersion near the magnetic zone boundary, which is not sensitive to the tilting of the global magnetic structure. We then use these parameters to calculate the low-energy spin-waves in the Néel state to reproduce the neutron response without strong antisymmetric coupling. Using Green's response functions, the stability of long-wavelength excitations in the context of our proposed untilted magnetic structures is then discussed. The results show the presence of strong symmetric exchange constants for the chiral exchange pathways and illustrate an underlying coupling between crystallographic and magnetic “chirality” through predominantly symmetric exchange. We further argue that the excitations can be consistently modelled in terms of an untilted magnetic structure in the presence of symmetric-only exchange constants.