Magnetic materials with noncoplanar magnetic structures can show unusual physical properties driven by nontrivial topology. Topologically-active states are often multi-q structures, which are challenging to stabilize in models and to identify in materials. Here, we use inelastic neutron-scattering experiments to show that the insulating double perovskites Ba2YRuO6 and Ba2LuRuO6 host a noncoplanar 3-q structure on the face-centered cubic lattice. Quantitative analysis of our neutron-scattering data reveals that these 3-q states are stabilized by biquadratic interactions. Our study identifies double perovskites as a highly promising class of materials to realize topological magnetism, elucidates the stabilization mechanism of the 3-q state in these materials, and establishes neutron spectroscopy on powder samples as a valuable technique to distinguish multi-q from single-q states, facilitating the discovery of topologically-nontrivial magnetic materials.
@article{arxiv.2301.11395,
title = {Cubic Double Perovskites Host Noncoplanar Spin Textures},
author = {Joseph A. M. Paddison and Hao Zhang and Jiaqiang Yan and Matthew J. Cliffe and Seung-Hwan Do and Shang Gao and Matthew B. Stone and David Dahlbom and Kipton Barros and Cristian D. Batista and Andrew D. Christianson},
journal= {arXiv preprint arXiv:2301.11395},
year = {2023}
}