Magnetic exchange interactions in the van der Waals layered antiferromagnet <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mi>Mn</mml:mi><mml:mi mathvariant="normal">P</mml:mi><mml:msub><mml:mi>Se</mml:mi><mml:mn>3</mml:mn></mml:msub></mml:mrow></mml:math>
Stuart Calder, Amanda V. Haglund, А. И. Колесников, David Mandrus
Abstract
Two-dimensional van der Waals compounds with magnetic ions on a honeycomb lattice are hosts to a variety of exotic behavior. The magnetic interactions in one such compound, $\mathrm{Mn}\mathrm{P}{\mathrm{Se}}_{3}$, are investigated with elastic and inelastic neutron scattering. Magnetic excitations are observed in the magnetically ordered regime and persist to temperatures well above the ordering temperature, ${T}_{\text{N}}=74\phantom{\rule{0.28em}{0ex}}\mathrm{K}$, consistent with low dimensional magnetic interactions. The inelastic neutron scattering results allow a model spin Hamiltonian to be presented that includes dominant intralayer interactions of ${J}_{1ab}=0.45$ meV, ${J}_{2ab}=0.03$ meV, ${J}_{3ab}=0.19$ meV, consistent with theoretical predictions. Despite the quasi-2D behavior, appreciable interlayer interactions of ${J}_{c}=0.031(5)$ meV are required to model the data. No evidence for anisotropy in the form of a spin gap is observed in the data collected. The measurements on $\mathrm{Mn}\mathrm{P}{\mathrm{Se}}_{3}$ are contrasted with those on $\mathrm{Mn}\mathrm{P}{\mathrm{S}}_{3}$ and reveal a large increase in the interlayer exchange interaction in $\mathrm{Mn}\mathrm{P}{\mathrm{Se}}_{3}$ that may stabilize the similar ordering temperatures in the bulk compounds.