Abstract
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=1.6K and TN2=0.6K. Magnetic Rietveld refinements indicate magnetic propagation vectors of the form q=(qx,qy,32), 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.
| Original language | English |
|---|---|
| Article number | 054423 |
| Journal | Physical Review B |
| Volume | 108 |
| Issue number | 5 |
| DOIs | |
| State | Published - Aug 1 2023 |
Funding
We are grateful to Andrew Christianson (ORNL) and Brenden Ortiz (ORNL) for valuable discussions. This work was supported by the U.S. Department of Energy (DOE), Office of Science, Basic Energy Sciences, Materials Sciences and Engineering Division, and used resources at the High Flux Isotope Reactor, a DOE Office of Science User Facility operated by the Oak Ridge National Laboratory. ACKNOWLEDGMENTS We are grateful to Andrew Christianson (ORNL) and Brenden Ortiz (ORNL) for valuable discussions. This work was supported by the U.S. Department of Energy (DOE), Office of Science, Basic Energy Sciences, Materials Sciences and Engineering Division, and used resources at the High Flux Isotope Reactor, a DOE Office of Science User Facility operated by the Oak Ridge National Laboratory.