Magnetic dynamics of NiPS3
Résumé
Neutron spectroscopy measurements have been performed on single crystals of the antiferromagnetic van der Waals compound NiPS3. Linear spin-wave theory using a Heisenberg Hamiltonian with single-ion anisotropies has been applied to determine the magnetic exchange parameters and the nature of the anisotropy. The analysis reveals that NiPS3 is less two-dimensional than its sister compounds, with a relatively large ferromagnetic exchange of J?=-0.3 meV between the layered ab planes. In-plane magnetic exchange interactions up to the third-nearest neighbor were required to fit the data. The nearest-neighbor exchange was ferromagnetic with J1=-2.6 meV, the second neighbor was antiferromagnetic and small with J2=0.2 meV, and the dominant antiferromagnetic third-neighbor exchange was J3=13.5 meV. The anisotropy was shown to be largely XY-like with a small uniaxial component, leading to the appearance of two low-energy spin wave modes in the spin-wave spectrum at the Brillouin zone center. The analysis could reproduce the spin-wave energies, however, there are discrepancies with the calculated neutron intensities, hinting at more exotic phenomena.
Mots clés
Anisotropy
Antiferromagnetism
Ferromagnetic materials
Ion exchange
Nickel compounds
Single crystals
Spin waves
Sulfur compounds
Van der Waals forces
Antiferromagnetics
Heisenberg
Linear spin-wave theory
Magnetic dynamics
Magnetic exchange
Nearest-neighbour
Neutron spectroscopy
Single ion anisotropy
Spectroscopy measurements
Van der Waals compound
Ferromagnetism
Domaines
Physique [physics]
Fichier principal
Wildes et al - 2022 - Magnetic dynamics of NiPS3.pdf (893.78 Ko)
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