Richness of spiral magnetic states in strontium ferrite thin films*

Perovskite strontium ferrite, SrFeO₃, hosts a variety of spiral magnetic phases at low temperature including multi-q states of different proper screw and/or cycloidal ordering ^[1]. Among them is a phase believed to support topologically-protected magnetic structures and may explain an observed finite-field anomaly in Hall effect ^[2].

SrFeO₃ is a fascinating material because these effects manifest despite the centrosymmetry of the crystal structure. Instead of a Dzyaloshinskii-Moriya interaction, the helimagnetism has been suggested to arise due to an interplay of electronic interactions ^[3].

Using resonant soft x-ray scattering, we study these complex magnetic orderings at low temperature on epitaxial thin films of SrFeO₃ grown by pulsed laser deposition. We find that the character of the spiral ordering depends on the substrate selected for growth, possibly indicating the influence of biaxial strain on the electronic interactions.

 

References

[1]   Ishiwata, S. et al. Versatile helimagnetic phases under magnetic fields in cubic perovskite SrFeO₃, Phys. Rev. B  84, 1–5 (2011).

[2]   Ishiwata, S. et al. Emergent topological spin structures in the centrosymmetric cubic perovskite SrFeO₃, Phys. Rev. B 101, 134406 (2020).

[3]   Mostovoy, M. Helicoidal ordering in iron perovskites, Phys. Rev. Lett. 94, 137205 (2005).