2023/04/18 by Joseph A. M. Paddison, Paddison, Joseph A. M., Yin Li +11
Physics and Astronomy · #Advanced Condensed Matter Physics #FOS: Physical sciences #Materials Science (cond-mat.mtrl-sci) #Strongly Correlated Electrons (cond-mat.str-el)
paper · pdf · doi:10.48550/arxiv.2304.08680
openalex publication_date 2023/04/18 · openalex created_date 2023/04/22 · openalex updated_date 2026/07/28
The kagome lattice can host exotic magnetic phases arising from frustrated and competing magnetic interactions. However, relatively few insulating kagome materials exhibit incommensurate magnetic ordering. Here, we present a study of the magnetic structures and interactions of antiferromagnetic Na2Mn3Cl8 with an undistorted Mn2+ kagome network. Using neutron-diffraction and bulk magnetic measurements, we show that Na2Mn3Cl8 hosts two different incommensurate magnetic states, which develop at TN1 = 1.6 K and TN2 = 0.6 K. Magnetic Rietveld refinements indicate magnetic propagation vectors of the form q = (qx,qy,(3)/(2)), and our neutron-diffraction data can be well described by cycloidal magnetic structures. By optimizing exchange parameters against magnetic diffuse-scattering data, we show that the spin Hamiltonian contains ferromagnetic nearest-neighbor and antiferromagnetic third-neighbor Heisenberg interactions, with a significant contribution from long-ranged dipolar coupling. This experimentally-determined interaction model is compared with density-functional-theory simulations. Using classical Monte Carlo simulations, we show that these competing interactions explain the experimental observation of multiple incommensurate magnetic phases and may stabilize multi-q states. Our results expand the known range of magnetic behavior on the kagome lattice.