Critical spin-flip scattering at the helimagnetic transition of MnSi
Critical spin-flip scattering at the helimagnetic transition of MnSi
复制标题
DOI：
10.1103/physrevb.89.180408
复制
发表时间：
2014-03
影响因子：
3.7
通讯作者：
J. Kindervater;W. Haussler;M. Janoschek;C. Pfleiderer;P. Boni;M. Garst
中科院分区：
文献类型：
--
作者：
J. Kindervater;W. Haussler;M. Janoschek;C. Pfleiderer;P. Boni;M. Garst
我们报道了球形中子偏振（SNP），并讨论了MnSi中自旋翻转散射截面以及接近helmagnetic跃迁的手性分数$\eta$。在我们的研究中，我们开发了一种小型化的SNP设备，当使用区域检测器进行小角度散射几何时，可以快速收集数据。发现临界自旋翻转散射是由动量空间中球上软化的手性顺子控制的。仔细考虑非相干自旋翻转背景，我们发现所得的手性分数$\eta$在helmagnetic跃迁以上逐渐减小，反映了一个强烈的重归一化的手性相关长度和温度依赖，与波动诱导的一阶跃迁的Brazovskii理论在数量上非常一致。
We report spherical neutron polarimetry (SNP) and discuss the spin-flip scattering cross sections as well as the chiral fraction $\eta$ close to the helimagnetic transition in MnSi. For our study, we have developed a miniaturised SNP device that allows fast data collection when used in small angle scattering geometry with an area detector. Critical spin-flip scattering is found to be governed by chiral paramagnons that soften on a sphere in momentum space. Carefully accounting for the incoherent spin-flip background, we find that the resulting chiral fraction $\eta$ decreases gradually above the helimagnetic transition reflecting a strongly renormalised chiral correlation length with a temperature dependence in excellent quantitative agreement with the Brazovskii theory for a fluctuation-induced first order transition.