Combining macroscopic measurements, neutron scattering and modeling, we identify in the GeFe2O4 spinel a correlated paramagnetic state resulting from the predominance of third-neighbor antiferromagnetic interactions. These interactions materialize 4 isolated families of triangular planes with 120∘ spins emerging from the underlying pyrochlore lattice. At lower temperatures, a phase transition occurs from this hierarchical spin liquid to a non-coplanar spin texture that is characterized by 6 propagating vectors. This unusual multi-q order is triggered by the presence of weaker interactions up to the sixth neighbors. The system is remarkably successful in coupling the different triangular planes while maintaining their two-dimensional 120∘ order. Our study highlights the hierarchy of interactions involved in GeFe2O4, which is singular among spinel compounds since first-neighbor interactions are only a small fraction of the dominant third neighbor ones.
@article{arxiv.2504.21142,
title = {From hierarchical triangular spin liquid to multi-$q$ spin texture in spinel GeFe$_2$O$_4$},
author = {L. Chaix and J. Robert and E. Chan and E. Ressouche and S. Petit and C. V. Colin and R. Ballou and J. Ollivier and L. -P. Regnault and E. Lhotel and V. Cathelin and S. Lenne and C. Cavanel and F. Damay and E. Suard and P. Strobel and C. Darie and S. deBrion and V. Simonet},
journal= {arXiv preprint arXiv:2504.21142},
year = {2025}
}