Magnetic structure and magnon dispersion in LaSrFeO${}_4$

Abstract

We present elastic and inelastic neutron scattering data on LaSrFeO${}_4$. We confirm the known magnetic structure with the magnetic moments lying in the tetragonal basal plane, but contrarily to previous reports our macroscopic and neutron diffraction data do not reveal any additional magnetic phase transition connected to a spin reorientation or to a redistribution of two irreducible presentations. Our inelastic neutron scattering data reveals the magnon dispersion along the main-symmetry directions [0 $\xi$ 0] and [$\xi$ -$\xi$ 0]. The dispersion can be explained within linear spin-wave theory yielding an antiferromagnetic nearest-neighbour interaction parameter $J_1=7.4(1)$ meV and a next-nearest neighbour interaction parameter $J_2=0.4(1)$ meV. The dispersion is gapped with the out-of-plane anisotropy gap found at ${\Delta }_{out}=5.26(2)$ meV, while evidence is present that the in-plane anisotropy gap lies at lower energies, where it cannot be determined due to limited instrument resolution.

9 pages, 11 figures

References in corpus (4)

• Magnetic correlations in La2-xSrxCoO4 studied by neutron scattering : possible evidence for stripe phases
• Neutron scattering studies on stripe phases in non-cuprate materials
• Magnetic spectrum of the two-dimensional antiferromagnet La2CoO4 studied by inelastic neutron scattering
• Melting of magnetic correlations in charge-orbital ordered La(0.5)Sr(1.5)MnO(4) : competition of ferro and antiferromagnetic states

Cited by in corpus (4)

• Temperature-dependent optical conductivity of layered LaSrFeO_4
• Strong magnetoelastic coupling at the transition from harmonic to anharmonic order in NaFe(WO${}_4$)${}_2$ with 3d${}^5$ configuration
• Anticollinear order and degeneracy lifting in square lattice antiferromagnet LaSrCrO4
• Random magnetic anisotropy driven transitions in layered perovskite LaSrCoO${}_4$