Spin-Wave Theory and its Applications to Neutron Scattering and THz
        Spectroscopy

Fishman, Randy

doi:10.1088/978-1-64327-114-9

Cited by 39 publications

(39 citation statements)

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“…We solve for the SW modes of these two models by performing a 1/S expansion about the classical limit and then diagonalizing a 2M × 2M equation-of-motion matrix 16,17 . Taking S = 5/2, the predicted INS intensities S(q, ω) are plotted in Fig.2 for all four cases with δ = 1/10 (M = 10 with p = 2 and δ = p/2M = 1/10 for AF interactions or p = 1 and δ = p/M = 1/10 for FM interactions).…”

Section: Mode Spectramentioning

confidence: 99%

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Normal modes of a spin cycloid or helix

2019

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Although spin cycloids and helices are quite common, remarkably little is known about the normal modes of a spin cycloid or helix with finite length on a discrete lattice. Based on simple onedimensional lattice models, we numerically evaluate the normal modes of a spin cycloid or helix produced by either Dzyaloshinskii-Moriya (DM) or competing exchange (CE) interactions. The normal modes depend on the type of interaction and on whether the nearest-neighbor exchange is antiferromagnetic (AF) or ferromagnetic (FM). In the AF/DM and FM/DM cases, there is only a single Goldstone mode; in the AF/CE and FM/CE cases, there are three. For FM exchange, the spin oscillations produced by non-Goldstone modes contain a mixture of tangential and transverse components. For the DM cases, we compare our numerical results with analytic results in the continuum limit. Examples are given of materials that fall into all four cases.

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Section: Mode Spectramentioning

confidence: 99%

“…The spin oscillation ∆S (n) r (q, t) at site r produced by SW mode n with wavevector q is generally given by 17,20…”

Section: Sw Amplitudes For Finite Lengthmentioning

confidence: 99%

Normal modes of a spin cycloid or helix

2019

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“…The method can be naturally extended to include other interactions such as Dzyaloshinskii-Moriya interaction, Ising interaction, and single-site magnetocrystalline anisotropy energy to the magnetic Hamiltonian, of relevance for the low-energy excitation spectra of quantum organometallic materials. Related to this we expect an even higher fraction of noncollinear ground states, for which the need for calculation of the spin wave dispersions with the more general framework of linear spin wave theory for noncollinear magnets is desired [56,57]. Furthermore, recent developments of machine learning techniques for lattice models and spin Hamiltonians, as for instance a profile method for recognition of three-dimensional magnetic structures [71], determination of phase transition temperatures by means of self-organizing maps [72], and a support vector machines based method for multiclassification of phases [73], will be most useful for identification and classification of competing magnetic phases at finite temperature, and the corresponding phase transition temperatures.…”

Section: Discussionmentioning

confidence: 99%

“…which can be related to the scattering intensity measured in inelastic neutron or electron scattering on magnetic materials. Only the magnetic excitations perpendicular to the scattering wave vector contribute to the scattering intensity [57,63]…”

Section: Atomistic Spin Dynamicsmentioning

confidence: 99%

Spin wave excitations of magnetic metalorganic materials

Hellsvik

Pérez

Geilhufe

et al. 2020

Phys. Rev. Materials

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The Organic Materials Database (OMDB) is an open database hosting about 22,000 electronic band structures, density of states and other properties for stable and previously synthesized 3dimensional organic crystals. The web interface of the OMDB offers various search tools for the identification of novel functional materials such as band structure pattern matching and density of states similarity search. In this work the OMDB is extended to include magnetic excitation properties. For inelastic neutron scattering we focus on the dynamical structure factor S(Q, ω) which contains information on the excitation modes of the material. We introduce a new dataset containing atomic magnetic moments and Heisenberg exchange parameters for which we calculate the spin wave spectra and dynamic structure factor with linear spin wave theory and atomistic spin dynamics. We thus develop the materials informatics tools to identify novel functional organic and metalorganic magnets.

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“…where f 2 (|q|) is the magnetic form factor for Mn 2+ ion, e −2W is the Debye-Waller factor, δ αβ is the Kronecker delta,q α is the α component of a unit vector in the direction of q, and S αβ (q, ω) is the response function that describes the αβ spin-spin correlations [45,46]. We also emphasize that the effective Hamiltonian is used for both the pure and doped MnWO 4 since the small amount of Co ions are uniformly distributed at the Mn sites and a description using averaged exchange interaction constants and anisotropy is justified.…”

Section: Introductionmentioning

confidence: 99%

Comprehensive inelastic neutron scattering study of the multiferroic Mn1−xCoxWO4

et al. 2018

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Using high-resolution inelastic neutron scattering, we examine the spin dynamics of Mn1−xCoxWO4 in the collinear AF1, the ac-b spiral AF2, and the ac cycloidal AF5 phases. The spin wave excitations are well described by a Heisenberg model with competing long-range exchange interactions (Ji up to 12 th nearest-neighbors) and the single-ion anisotropy K induced by the spinorbit interaction. While the exchange constants are relatively unchanged, the dominant effect of doping is to change the single-ion anisotropy from easy axis (K > 0) in the collinear AF1 phase to easy plane (K < 0) in the two multiferroic phases.

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Spin-Wave Theory and its Applications to Neutron Scattering and THz Spectroscopy

Cited by 39 publications

References 0 publications

Normal modes of a spin cycloid or helix

Normal modes of a spin cycloid or helix

Spin wave excitations of magnetic metalorganic materials

Comprehensive inelastic neutron scattering study of the multiferroic Mn1−xCoxWO4

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