Magnetic spectrum of the two-dimensional antiferromagnet La2CoO4 studied by inelastic neutron scattering

Abstract

We report measurements of the magnetic excitation spectrum of the layered antiferromagnet La2CoO4 by time-of-flight neutron inelastic scattering. In the energy range probed in our experiments (0-250 meV) the magnetic spectrum consists of spin-wave modes with strong in-plane dispersion extending up to 60 meV, and a nearly dispersionless peak at 190 meV. The spin-wave modes exhibit a small (~1 meV) dispersion along the magnetic zone boundary. We show that the magnetic spectrum can be described very well by a model of a Heisenberg antiferromagnet that includes the full spin and orbital degrees of freedom of Co2+ in an axially-distorted crystal field. The collective magnetic dynamics are found to be controlled by dominant nearest-neighbour exchange interactions, strong XY-like single-ion anisotropy and a substantial unquenched orbital angular momentum.

8 pages, 7 figures

References in corpus (8)

• Spin blockade, orbital occupation and charge ordering in La_(1.5)Sr_(0.5)CoO4
• Quantum dynamics and entanglement of spins on a square lattice
• Magnetic correlations in La2-xSrxCoO4 studied by neutron scattering : possible evidence for stripe phases
• Optical Spectroscopy in CoO: Phonons, Electric, and Magnetic Excitations
• Magnetic order and dynamics of the charge-ordered antiferromagnet La1.5Sr0.5CoO4
• Anisotropic Susceptibility of La_2-xSr_xCoO_4 related to the Spin States of Cobalt
• Spin and charge orders and their hole-doping dependence in single layered cobaltate La2-xCaxCoO4(0.3<x<0.8)
• Stripeless incommensurate magnetism in a doped strongly correlated oxide

Cited by in corpus (8)

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• Hour-glass magnetic excitations induced by nanoscopic phase separation in cobalt oxides La${}_{2-x}$Sr${}_x$CoO${}_4$
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• Evidence for a temperature-induced spin-state transition of Co3+ in La2-xSrxCoO4
• Disorder, cluster spin glass, and hour-glass spectra in striped magnetic insulators
• High-energy spin waves in the spin-1 square-lattice antiferromagnet La${}_2$NiO${}_4$
• Prediction of Room Temperature Electric Field Reversal of Magnetization in the Family of $A_4{B}_3{\mathrm{O}}_9$ Layered Oxides
• Anticollinear order and degeneracy lifting in square lattice antiferromagnet LaSrCrO4