Lattice dynamics in the double-helix antiferromagnet FeP

Sukhanov, A. S.; Nikitin, S. E.; Pavlovskiĭ, M. S.; Sterling, Tyler C.; Andryushin, N. D.; Cameron, A. S.; Tymoshenko, Y. V.; Walker, Helen C.; Morozov, Igor; Chernyavskii, I. O.; Aswartham, Saicharan; Reznik, D.; Inosov, D. S.

doi:10.1103/physrevresearch.2.043405

“…The magnon dispersion reaches an energy of ∼25 meV at the BZ boundary at Q = (1 1 ±0.5), where a weakly dispersing intense optic-phonon mode is observed above the magnon band. The phonon mode disperses weakly also for the H direction, but has a pronounced dispersion down to ∼15 meV along K. The assessment of the phonon mode as an optic phonon is based on the previous detailed study of the lattice vibrations in FeP [44]. The fact that the magnon bandwidth along the L direction in momentum space is bounded by E = 25 meV is confirmed by the absence of any INS intensity at higher energies at least up to ∼55 meV covered in the collected dataset.…”

Section: A Observed Spectramentioning

confidence: 99%

Frustration model and spin excitations in the helimagnet FeP

Sukhanov

¹

,

Tymoshenko

²

,

Kulbakov

³

et al. 2022

Self Cite

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The metallic compound FeP belongs to the class of materials that feature a complex noncollinear spin order driven by magnetic frustration. While its double-helix magnetic structure with a period λ s ≈ 5c, where c is the lattice constant, was previously well determined, the relevant spin-spin interactions that lead to that ground state remain unknown. By performing extensive inelastic neutron scattering measurements, we obtained the spin-excitation spectra in a large part of the momentum-energy space. The spectra show that the magnons are gapped with a gap energy of ∼5 meV. Despite the 3D crystal structure, the magnon modes display strongly anisotropic dispersions, revealing a quasi-one-dimensional character of the magnetic interactions in FeP. The physics of the material, however, is not determined by the dominating exchange, which is ferromagnetic. Instead, the weaker two-dimensional antiferromagnetic interactions between the rigid ferromagnetic spin chains drive the magnetic frustration. Using linear spin-wave theory, we were able to construct an effective Heisenberg Hamiltonian with an anisotropy term capable of reproducing the observed spectra. This enabled us to quantify the exchange interactions in FeP and determine the mechanism of its magnetic frustration.

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“…To summarize, Phonon Explorer software has been successfully used in three completed research projects spanning a variety of experimental conditions [9,13,14].…”

Section: Discussionmentioning

confidence: 99%

“…It has been successfully applied to cases where a measurement of all phonons is desired as well as to projects focusing on specific phonons or phonon branches [9,13,14]. Here we focus on phonons mostly because their scattering intensity is greatest at large wavevectors where manually going through every Brillouin zone is especially time-consuming.…”

Section: Introductionmentioning

confidence: 99%

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Automating Analysis of Neutron Scattering Time-of-Flight Single Crystal Phonon Data

Reznik

¹

,

Ahmadova

²

2020

QuBS

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This article introduces software called Phonon Explorer that implements a data mining workflow for large datasets of the neutron scattering function, S(Q, ω), measured on time-of-flight neutron spectrometers. This systematic approach takes advantage of all useful data contained in the dataset. It includes finding Brillouin zones where specific phonons have the highest scattering intensity, background subtraction, combining statistics in multiple Brillouin zones, and separating closely spaced phonon peaks. Using the software reduces the time needed to determine phonon dispersions, linewidths, and eigenvectors by more than an order of magnitude.

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“…The magnon dispersion reaches an energy of ∼25 meV at the BZ boundary at Q = (1 1 ± 0.5), where a weakly dispersing intense optic-phonon mode is observed above the magnon band. The assessment of the flat mode at E = 30 meV as an optic phonon is based on the previous detailed study of the lattice vibrations in FeP [44]. The fact that the magnon bandwidth along the L direction in momentum space is bounded by E = 25 meV is confirmed by the absence of any INS intensity at higher energies at least up to ∼55 meV covered in the collected dataset.…”

Section: Tof Spectroscopy a Observed Spectramentioning

confidence: 99%

Frustration model and spin excitations in the helimagnet FeP

Sukhanov,

Tymoshenko,

Kulbakov

et al. 2022

Preprint

Self Cite

0

View full text Add to dashboard Cite

The metallic compound FeP belongs to the class of materials that feature a complex noncollinear spin order driven by magnetic frustration. While its double-helix magnetic structure with a period λ s ≈ 5c, where c is the lattice constant, was previously well determined, the relevant spin-spin interactions that lead to that ground state remain unknown. By performing extensive inelastic neutron scattering measurements, we obtained the spin-excitation spectra in a large part of the momentum-energy space. The spectra show that the magnons are gapped with a gap energy of ∼5 meV. Despite the 3D crystal structure, the magnon modes display strongly anisotropic dispersions, revealing a quasi-one-dimensional character of the magnetic interactions in FeP. The physics of the material, however, is not determined by the dominating exchange, which is ferromagnetic. Instead, the weaker two-dimensional antiferromagnetic interactions between the rigid ferromagnetic spin chains drive the magnetic frustration. Using linear spin-wave theory, we were able to construct an effective Heisenberg Hamiltonian with an anisotropy term capable of reproducing the observed spectra. This enabled us to quantify the exchange interactions in FeP and determine the mechanism of its magnetic frustration.

show abstract

Lattice dynamics in the double-helix antiferromagnet FeP

Cited by 6 publications

References 54 publications

Frustration model and spin excitations in the helimagnet FeP

Frustration model and spin excitations in the helimagnet FeP

Automating Analysis of Neutron Scattering Time-of-Flight Single Crystal Phonon Data

Frustration model and spin excitations in the helimagnet FeP

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