μ⁺SR揭示Weyl半金属Mn₃Sn中的微观磁相演化
Microscopic magnetic phase evolution in the Weyl semimetal Mn$_3$Sn revealed by $μ^+$SR
- KTH Royal Institute of Technology（皇家理工学院）
- Uppsala University（乌普萨拉大学）
- PSI Center for Neutron and Muon Sciences CNM（瑞士保罗谢勒研究所中子与μ子科学中心）
- University of Luxembourg（卢森堡大学）
- Forschungszentrum Jülich GmbH（于利希研究中心有限公司）
- TRIUMF（特利昂夫实验室）
- Institut Laue-Langevin（朗之万-桂良研究所）
- RWTH Aachen（亚琛工业大学）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
本研究通过μ⁺SR技术确定Mn₃Sn的磁相转变温度，发现其低温无静态自旋玻璃态，磁结构受非谐性修饰，磁环境随温度连续演化，揭示了该Weyl半金属的动态磁相行为。
AI中文摘要：
我们报道了对反铁磁（AFM）Weyl半金属Mn₃Sn（成分为Mn₂.₉₉Sn）开展的综合μ⁺SR（μ子自旋弛豫）与体磁化研究。据报道Mn₃Sn具有公度逆三角（IT）AFM相、无公度（IC）螺旋AFM相，以及被提出的低温类自旋玻璃态。在我们的样品中，确定了这些相的各自转变温度：奈尔温度T_N=418 K、相变温度T_t≈275 K、冻结温度T_f=21 K。对T_f以下的低温区域研究，未发现静态自旋玻璃态的证据；相反，样品呈现出铁磁（FM）分量增加，同时伴随自旋涨落的局域减慢，表明这些现象可能是解耦的。在IC螺旋AFM相中，对零场（ZF）谱的拟合揭示了不对称的内部磁场分布，说明磁结构因非谐性而发生了显著改变。在温度升至150 K以上时，μ子谱权重的连续重分布揭示了一个宽范围的共存局域磁环境，与IC螺旋相和IT-AFM相相关。在T_t以上的公度IT-AFM相中，初始不对称性中持续存在的缺失部分表明，对应于样品相关不对称性约20%的一部分注入μ子，经历了未分辨的超快退极化。最后，我们在325 K以上观察到μ子位点布居的温度驱动偏移。最终，我们的结果显示Mn₃Sn中存在高度动态的磁环境，表明其复杂磁有序常随温度连续共存与演化。
英文摘要：
We report a comprehensive muon spin relaxation ($μ^+$SR) and bulk magnetization study of the antiferromagnetic (AFM) Weyl semimetal Mn$_3$Sn (composition Mn${2.99}$Sn). Mn$3$Sn is reported to exhibit a commensurate inverse triangular (IT) AFM phase, an incommensurate (IC) helical AFM phase, and a proposed low-temperature spin-glass-like state. In our sample, we identify the characteristic temperatures associated with these regimes as N'eel temperature ($T\mathrm{N} = 418$ K), a macroscopic bulk transition temperature between IT-AFM to IC helical phase ($T\mathrm{t} \approx 275$ K), and low-temperature transition $T_\mathrm{f} = 21$ K. Investigating the low-temperature regime below $T_\mathrm{f}$, we find no evidence of a static spin-glass state. Instead, the sample exhibits an increasing ferromagnetic (FM) component accompanied by a localized slowing of spin fluctuations, indicating that these phenomena may be decoupled. In the IC helical AFM phase, the zero-field (ZF) spectra are best described by damped oscillations with an empirical phase offset, consistent with anharmonic and amplitude-modulated order reported by scattering studies. Upon warming above 150 K, a continuous redistribution of muon spectral weight reveals a broad, homogeneous magnetic crossover between the IC helical and IT-AFM phases. In the commensurate IT-AFM phase above $T_\mathrm{t}$, a persistent missing fraction in the initial asymmetry indicates that a subset of implanted muons, corresponding to roughly 20% of the sample-related asymmetry, undergoes unresolved ultrafast depolarization. Finally, we observe temperature-driven shifts in muon site populations above 325 K. Ultimately, our results show a highly dynamic magnetic landscape in Mn$_3$Sn, demonstrating how its complex magnetic orders often coexist and evolve continuously with temperature.
