High-energy spin waves in the spin-1 square-lattice antiferromagnet La${}_2$NiO${}_4$

A. N. Petsch, N. S. Headings, D. Prabhakaran +5

Inelastic neutron scattering is used to study the magnetic excitations of the $S=1$ square-lattice antiferromagnet La${}_2$NiO${}_4$. We find that the spin waves cannot be described by…