Seewald, F.Schulze, T.Gräßler, N.Carstens, F. L.Singer, L.Mohamed, M. A. A.Hampel, S.Büchner, B.Klingeler, R.Klauss, H.-H.Grafe, H.-J.2025-08-292025-08-292025-08-29https://opara.zih.tu-dresden.de/handle/123456789/1667https://doi.org/10.25532/OPARA-931The recently discovered lithium-rich antiperovskites (Li2Fe)SeO and (Li2Fe)SO host lithium and iron ions on the same atomic position which octahedrally coordinates to central oxygens. In a cubic antiperovskite these sites form Kagome planes stacked along the < 111 > directions which triangular motifs induce high geometric frustration in the diluted magnetic sublattice for antiferromagnetic interactions. Despite their compelling properties as high-capacity Li-ion battery cathode materials, very little is known about the electronic and magnetic properties of lithium-rich antiperovskites. We report static magnetization, M¨ossbauer, and NMR studies on both compounds. Our data reveal a Pauli paramagnetic-like behaviour, a long-range antiferromagnetically ordered ground state below ≈ 50 K and a regime of short-range magnetic correlations up to 100 K. Our results are consistent with a random Li-Fe distribution on the shared lattice position. In addition, Li-hopping is observed above 200 K with an activation energy of Ea = 0.47 eV. Overall, our data elucidate static magnetism in a disordered magnetically frustrated and presumably semimetallic system with thermally induced ion diffusion dynamics.Attribution-NonCommercial 4.0 Internationalhttp://creativecommons.org/licenses/by-nc/4.0/3::32::307