EuAl $_4$和EuGa $_4$拓扑反铁磁体的自旋序和涨落：$μ$ SR研究
Spin order and fluctuations in the EuAl$_4$ and EuGa$_4$ topological antiferromagnets: A $μ$SR study
摘要：
我们报告的系统μ子自旋旋转和弛豫（$μ$ SR）的磁性EuAl $_4$和EuGa $_4$单晶在微观水平上的研究。横向场$μ$ SR测量，跨越一个很宽的温度范围（从1.5到50 K），显示出清晰的体原子力显微镜过渡，在这两种情况下，几乎100%的磁性体积分数。零场$μ$ SR测量，涵盖了AFM和顺磁（PM）状态，揭示了内部磁场$B_\mathrm{int}(0) = 0.33$ T和0.89 T的EuAl $_4$和EuGa $_4$，分别。横向μ子自旋弛豫率$λ_\mathrm{T}$，在μ子停止站点的内部场分布的措施，显示出对比的行为。在EuGa $_4$中，它随着温度的降低而减小，在零温度时达到最小值，$λ_\mathrm{T}(0) = 0.71$ $μ$ s $^{-1}$。在EuAl $_4$中，它显著增加低于$T_\mathrm{N}$，在1.5 K下达到58 $μ$ s $^{-1}$，最有可能反映了EuAl $_4$的AFM状态中的复杂磁结构和竞争相互作用。在这两种化合物中，温度依赖的纵向μ子自旋弛豫$λ_\mathrm{L}(T)$，自旋波动率的指示，发散附近的AFM顺序的发病，随后在$T < T_\mathrm{N}$显着下降。在AFM状态下，自旋波动在EuAl $_4$中比在EuGa $_4$中强得多，而在PM状态下相当。由$μ$ SR提供的对外部磁场的强大的自旋波动的证据可能提供新的见解的起源的拓扑霍尔效应和可能的磁skyrmions在EuAl $_4$和EuGa $_4$化合物。
英文摘要：
We report on systematic muon-spin rotation and relaxation ($μ$SR) studies of the magnetic properties of EuAl$_4$ and EuGa$_4$ single crystals at a microscopic level. Transverse-field $μ$SR measurements, spanning a wide temperature range (from 1.5 to 50 K), show clear bulk AFM transitions, with an almost 100% magnetic volume fraction in both cases. Zero-field $μ$SR measurements, covering both the AFM and the paramagnetic (PM) states, reveal internal magnetic fields $B_\mathrm{int}(0) = 0.33$ T and 0.89 T in EuAl$_4$ and EuGa$_4$, respectively. The transverse muon-spin relaxation rate $λ_\mathrm{T}$, a measure of the internal field distribution at the muon-stopping site, shows a contrasting behavior. In EuGa$_4$, it decreases with lowering the temperature, reaching its minimum at zero temperature, $λ_\mathrm{T}(0) = 0.71$ $μ$s$^{-1}$. In EuAl$_4$, it increases significantly below $T_\mathrm{N}$, to reach 58 $μ$s$^{-1}$ at 1.5 K, most likely reflecting the complex magnetic structure and the competing interactions in the AFM state of EuAl$_4$. In both compounds, the temperature-dependent longitudinal muon-spin relaxation $λ_\mathrm{L}(T)$, an indication of the rate of spin fluctuations, diverges near the onset of AFM order, followed by a significant drop at $T < T_\mathrm{N}$. In the AFM state, spin fluctuations are much stronger in EuAl$_4$ than in EuGa$_4$, while being comparable in the PM state. The evidence of robust spin fluctuations against the external magnetic fields provided by $μ$SR may offer new insights into the origin of the topological Hall effect and the possible magnetic skyrmions in the EuAl$_4$ and EuGa$_4$ compounds.
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。
