The discovery of new magnetic ground states in geometrically frustrated lattices remains a central challenge in materials science. Here, we report the synthesis, structural characterization, and frustrated magnetic properties of FeGe3O4, a newly identified compound that crystallizes in the noncentrosymmetric cubic space group P213. In this structure, Fe atoms form an intricate double-trillium lattice with nearest-neighbor Fe--Fe distances of ∼4.2~\AA{}, while Ge2+ ions mediate magnetic interactions through Fe-Ge-Fe pathways. Field-dependent magnetization at 2~K shows a pronounced nonlinearity, reaching a maximum moment of 2.55(3)~μB/Fe2+ at 70~kOe without evidence of saturation. Magnetic susceptibility, heat capacity, and neutron scattering collectively reveal the onset of short-range magnetic interactions near 5~K, with no long-range ordering detected down to 0.06~K. Specific heat measurements demonstrate strong frustration: only ∼34\% of the expected magnetic entropy is recovered at 2.4~K. Taken together, these results establish FeGe3O4 as a rare example of a geometrically frustrated trillium-lattice magnet, offering a promising platform for exploring exotic quantum magnetic phenomena.
@article{arxiv.2601.08947,
title = {Frustrated Magnetism in FeGe$_3$O$_4$ with a Chiral Trillium Network},
author = {Matt Boswell and Mingyu Xu and Haozhe Wang and Mouyang Cheng and N. Li and X. F. Sun and Haidong Zhou and Huibo Cao and Mingda Li and Weiwei Xie},
journal= {arXiv preprint arXiv:2601.08947},
year = {2026}
}