paper

Magnetism of the Fe $^{2 +}$ and Ce $^{3 +}$ sublattices in Ce $_{2}$ O $_{2}$ FeSe $_{2}$ : a combined neutron powder diffraction, inelastic neutron scattering and density functional study

arXiv:1412.1773 · doi:10.1103/PhysRevB.90.235115

Abstract

The discovery of superconductivity in the 122 iron selenide materials above 30 K necessitates an understanding of the underlying magnetic interactions. We present a combined experimental and theoretical investigation of magnetic and semiconducting Ce $_{2}$ O $_{2}$ FeSe $_{2}$ composed of chains of edge-linked iron selenide tetrahedra. The combined neutron diffraction and inelastic scattering study and density functional calculations confirm the ferromagnetic nature of nearest-neighbour Fe -- Se -- Fe interactions in the ZrCuSiAs-related iron oxyselenide Ce $_{2}$ O $_{2}$ FeSe $_{2}$ . Inelastic measurements provide an estimate of the strength of nearest-neighbor Fe -- Fe and Fe -- Ce interactions. These are consistent with density functional theory calculations, which reveal that correlations in the Fe--Se sheets of Ce $_{2}$ O $_{2}$ FeSe $_{2}$ are weak. The Fe on-site repulsion $U_{F e}$ is comparable to that reported for oxyarsenides and K $_{1 - x}$ Fe $_{2 - y}$ Se $_{2}$ , which are parents to iron-based superconductors.

(12 pages, 7 figures, to appear in Phys. Rev. B)

Magnetism of the Fe2+ and Ce3+ sublattices in Ce2​O2​FeSe2​: a combined neutron powder diffraction, inelastic neutron scattering and density functional study

Abstract

Magnetism of the Fe $^{2 +}$ and Ce $^{3 +}$ sublattices in Ce $_{2}$ O $_{2}$ FeSe $_{2}$ : a combined neutron powder diffraction, inelastic neutron scattering and density functional study