Magnetoelastic mapping of the high-field phase diagram in the topological cubic helimagnet SrFeO${}_3$

Abstract

The cubic perovskite SrFeO${}_3$ is a prototypical centrosymmetric itinerant magnet that hosts a quadruple-$\mathbf{Q}$ hedgehog-antihedgehog lattice and exhibits a complex magnetic-field-temperature phase diagram. Yet, the microscopic mechanism underlying the emergence of its versatile multiple-$\mathbf{Q}$ phases remains unresolved. Here, we reveal the field-orientation dependence of the magnetic phase diagram and establish an effective spin Hamiltonian for SrFeO${}_3$ that incorporates a cubic single-ion anisotropy together with bilinear and biquadratic interactions in momentum space, which originate from the spin-charge coupling. In addition, we observe magnetoelastic signatures of a redistribution of the ligand-hole density upon entering the forced ferromagnetic phase. These findings emphasize the pivotal importance of electronic itinerancy arising from the formation of a ligand-hole band in stabilizing multiple-$\mathbf{Q}$ phases.

11 pages, 5 figures, SM: 7 pages, 6 figures