Reentrant multiple-q magnetic order and a “spin meta-cholesteric” phase in Sr3Fe2O7

• Published in: npj quantum materials Vol. 9; no. 1; pp. 84 - 6
• Main Authors: Andriushin, N. D., Muller, J., Pavlovskii, N. S., Grumbach, J., Granovsky, S., Tymoshenko, Y. V., Zaharko, O., Ivanov, A., Ollivier, J., Doerr, M., Keimer, B., Mostovoy, M., Inosov, D. S., Peets, D. C.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 26.10.2024; Nature Publishing Group; Nature Portfolio
• Subjects: 639/301/119/997; 639/766/119/997; Condensed Matter Physics; Hypothetical particles; Lattices; Melts (crystal growth); Particle theory; Perovskites; Physics; Physics and Astronomy; Quantum Physics; State vectors; Structural Materials; Surfaces and Interfaces; Symmetry; Thin Films
• ISSN: 2397-4648; 2397-4648
• DOI: 10.1038/s41535-024-00698-4

Topologically nontrivial magnetic structures such as skyrmion lattices are well known in materials lacking lattice inversion symmetry, where antisymmetric exchange interactions are allowed. Only recently, topological multi- q magnetic textures that spontaneously break the chiral symmetry, for example, three-dimensional hedgehog lattices, were discovered in centrosymmetric compounds, where they are instead driven by frustrated interactions. Here we show that the bilayer perovskite Sr 3 Fe 2 O 7 , previously believed to adopt a simple single- q spin-helical order, hosts two distinct types of multi- q spin textures. Its ground state represents a novel multi- q spin texture with unequally intense spin modulations at the two ordering vectors. This is followed in temperature by a new “spin meta-cholesteric” phase, in which the chiral symmetry is spontaneously broken along one of the crystal directions, but the weaker orthogonal modulation melts, giving rise to intense short-range dynamical fluctuations. Shortly before the transition to the paramagnetic state, vortex-crystal order spanned by two equivalent q vectors emerges. This renders Sr 3 Fe 2 O 7 an ideal material to study transitions among multiple- q spin textures in a centrosymmetric host.