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

Peter Adle, Manfred Reehuis, Norbert Stüßer, Sergey A. Medvedev, Michael Nicklas, Darren C. Peets, Joel Bertinshaw, Christian Kolle Christensen, Martin Etter, Andreas Hoser, Liane Schröder,, Patrick Merz, Walter Schnelle, Armin Schulz, Qingge Mu, Dimitrios Bessas, Aleksandr Chumakov, Martin Jansen, Claudia Felser

Publikation: Bidrag til tidsskriftTidsskriftartikelForskningpeer review

Abstrakt

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-Δ insulator 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 57Fe-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.
OriginalsprogEngelsk
Artikelnummer054417
TidsskriftPhysical Review B
Vol/bind105
Udgave nummer5
Antal sider10
ISSN2469-9950
DOI
StatusUdgivet - 17. feb. 2022
Udgivet eksterntJa

Fingeraftryk

Dyk ned i forskningsemnerne om 'Spiral magnetism, spin flop, and pressure-induced ferromagnetism in the negative charge-transfer-gap insulator Sr2FeO4'. Sammen danner de et unikt fingeraftryk.

Citationsformater