English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

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 wavescannot be described by a simple classical (harmonic) Heisenberg model with onlynearest-neighbor interactions. The spin-wave dispersion measured along theantiferromagnetic Brillouin-zone boundary shows a minimum energy at the$(1/2,0)$ position as is observed in some $S=1/2$ square-latticeantiferromagnets. Thus, our results suggest that the quantum dispersionrenormalization effects or longer-range exchange interactions observed incuprates and other $S=1/2$ square-lattice antiferromagnets are also present inLa$_2$NiO$_4$. We also find that the overall intensity of the spin-waveexcitations is suppressed relative to linear spin-wave theory indicating thatcovalency is important. Two-magnon scattering is also observed.

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