Spiral magnetism, spin flop, and pressure-induced ferromagnetism in the negative charge-transfer-gap insulator Sr2FeO4

Adler P, Reehuis M, Stuesser N, Medvedev SA, Nicklas M, Peets DC, Bertinshaw J, Christensen CK, Etter M, Hoser A, Schroeder L, Merz P, Schnelle W, Schulz A, Mu Q, Bessas D, Chumakov A, Jansen M, Felser C (2022)

Publication Type: Journal article

Publication year: 2022

Journal

Physical Review B American Physical Society

Book Volume: 105

Article Number: 054417

Journal Issue: 5

DOI: 10.1103/PhysRevB.105.054417

Abstract

Iron(IV) oxides are strongly correlated materials with negative charge-transfer energy (negative Δ), and exhibit peculiar electronic and magnetic properties such as topological helical spin structures in the metallic cubic perovskite SrFeO3. Here, the spin structure of the layered negative-Δinsulator Sr2FeO4 was studied by powder neutron diffraction in zero field and magnetic fields up to 6.5 T. Below TN=56K, Sr2FeO4 adopts an elliptical cycloidal spin structure with modulated magnetic moments between 1.9 and 3.5 μB and a propagation vector k=(τ,τ,0) with τ=0.137. With increasing magnetic field the spin structure undergoes a spin-flop transition near 5 T. Synchrotron Fe57-Mössbauer spectroscopy reveals that the spin spiral transforms to a ferromagnetic structure at pressures between 5 and 8 GPa, just in the pressure range where a Raman-active phonon nonintrinsic to the K2NiF4-type crystal structure vanishes. These results indicate an insulating ground state which is stabilized by a hidden structural distortion and differs from the charge disproportionation in other Fe(IV) oxides.

Involved external institutions

Helmholtz-Zentrum Berlin für Materialien und Energie (HZB) DE Germany (DE) Deutsches Elektronen-Synchrotron DESY DE Germany (DE) Max-Planck-Institut für Chemische Physik fester Stoffe (MPI CPfS) / Max Planck Institute for Chemical Physics of Solids DE Germany (DE) Technische Universität Dresden DE Germany (DE) Max-Planck-Institut für Festkörperforschung DE Germany (DE) European Synchrotron Radiation Facility (ESRF) FR France (FR)

How to cite

APA:

Adler, P., Reehuis, M., Stuesser, N., Medvedev, S.A., Nicklas, M., Peets, D.C.,... Felser, C. (2022). Spiral magnetism, spin flop, and pressure-induced ferromagnetism in the negative charge-transfer-gap insulator Sr2FeO4. Physical Review B, 105(5). https://doi.org/10.1103/PhysRevB.105.054417

MLA:

Adler, Peter, et al. "Spiral magnetism, spin flop, and pressure-induced ferromagnetism in the negative charge-transfer-gap insulator Sr2FeO4." Physical Review B 105.5 (2022).

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