Baral Priya R, Ukleev Victor, Živković Ivica, Lee Youngro, Orlandi Fabio, Manuel Pascal, Skourski Yurii, Keller Lukas, Stunault Anne, Rodríguez-Velamazán J Alberto, Cubitt Robert, Magrez Arnaud, White Jonathan S, Mazin Igor I, Zaharko Oksana
Department of Applied Physics and Quantum-Phase Electronics Center, The University of Tokyo, Bunkyo-ku, Japan.
Laboratory for Neutron Scattering and Imaging (LNS), PSI Center for Neutron and Muon Sciences, Villigen, PSI, Switzerland.
Nat Commun. 2025 Apr 24;16(1):3898. doi: 10.1038/s41467-025-58933-w.
The topological Hall effect (THE) is a hallmark of a non-trivial geometric spin arrangement in a magnetic metal, originating from a finite scalar spin chirality (SSC). The associated Berry phase is often a consequence of non-coplanar magnetic structures identified by multiple k-vectors. For single - k magnetic structures however with zero SSC, the emergence of a finite topological Hall signal presents a conceptual challenge. Here, we report that a fluctuation-driven mechanism involving chiral magnons is responsible for the observed THE in a low-symmetry compound, monoclinic FeGa. Through neutron scattering experiments, we discovered several nontrivial magnetic phases in this system. In our focus is the helical spiral phase at room temperature, which transforms into a transverse conical state in applied magnetic field, supporting a significant THE signal up to and above room temperature. Our work offers a fresh perspective in the search for novel materials with intertwined topological magnetic and transport properties.
拓扑霍尔效应（THE）是磁性金属中非平凡几何自旋排列的一个标志，源于有限的标量自旋手性（SSC）。相关的贝里相位通常是由多个k矢量识别出的非共面磁结构的结果。然而，对于具有零SSC的单k磁结构，有限拓扑霍尔信号的出现提出了一个概念性挑战。在这里，我们报告一种涉及手性磁振子的涨落驱动机制是导致在低对称化合物单斜晶系FeGa中观察到的THE的原因。通过中子散射实验，我们在这个系统中发现了几个非平凡磁相。我们关注的是室温下的螺旋螺旋相，它在施加磁场时转变为横向圆锥态，在室温及以上温度都支持显著的THE信号。我们的工作为寻找具有相互交织的拓扑磁性和输运性质的新型材料提供了一个新的视角。
