Neutron diffraction on the centrosymmetric square-net magnet EuGa2Al2 reveals multiple incommensurate magnetic states (AFM1,2,3) in zero field. In applied field, a new magnetic phase (A) is identified from magnetization and transport measurements, bounded by two of the μ0H~=~0 incommensurate magnetic phases (AFM1,helical and AFM3, cycloidal) with different moment orientations. Moreover, magneto-transport measurements indicate the presence of a topological Hall effect, with maximum values centered in the A phase. Together, these results render EuGa2Al2 a material with non-coplanar or topological spin texture in applied field. X-ray diffraction reveals an out-of-plane (OOP) charge density wave (CDW) below TCDW∼ 50 K while the magnetic propagation vector lies in plane below TN = 19.5 K. Together these data point to a new route to realizing in-plane non-collinear spin textures through an OOP CDW. In turn, these non-collinear spin textures may be unstable against the formation of topological spin textures in an applied field.
@article{arxiv.2110.11935,
title = {Incommensurate magnetic orders and topological Hall effect in the square-net centrosymmetric EuGa$_2$Al$_2$ system},
author = {Jaime M. Moya and Shiming Lei and Eleanor M. Clements and Caitlin S. Kengle and Stella Sun and Kevin Allen and Qizhi Li and Y. Y. Peng and Ali A. Husain and Matteo Mitrano and Matthew J. Krogstad and Raymond Osborn and Anand B. Puthirath and Songxue Chi and L. Debeer-Schmitt and J. Gaudet and P. Abbamonte and Jeffrey W. Lynn and E. Morosan},
journal= {arXiv preprint arXiv:2110.11935},
year = {2022}
}