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Bloch equations in terahertz magnetic-resonance ellipsometry

Rindert, Viktor LU orcid ; Richter, Steffen LU ; Kühne, Philipp ; Ruder, Alexander ; Darakchieva, Vanya LU and Schubert, Mathias LU orcid (2024) In Physical Review B 110(5).
Abstract

A generalized approach derived from Bloch's equation of motion of nuclear magnetic moments is presented to model the frequency, magnetic field, spin density, and temperature dependencies in the electromagnetic permeability tensor for materials with magnetic resonances. The resulting tensor model predicts characteristic polarization signatures which can be observed, for example, in Mueller matrix element spectra measured. When augmented with thermodynamic considerations and suitable Hamiltonian description of the magnetic eigenvalue spectrum, important parameters such as density, spectral amplitude distribution, relaxation time constants, and geometrical orientation parameters of the magnetic moments can be obtained from comparing the... (More)

A generalized approach derived from Bloch's equation of motion of nuclear magnetic moments is presented to model the frequency, magnetic field, spin density, and temperature dependencies in the electromagnetic permeability tensor for materials with magnetic resonances. The resulting tensor model predicts characteristic polarization signatures which can be observed, for example, in Mueller matrix element spectra measured. When augmented with thermodynamic considerations and suitable Hamiltonian description of the magnetic eigenvalue spectrum, important parameters such as density, spectral amplitude distribution, relaxation time constants, and geometrical orientation parameters of the magnetic moments can be obtained from comparing the generalized model approach to experimental data. We demonstrate our approach by comparing model calculations with full Mueller matrix element spectra measured at an oblique angle of incidence in the terahertz spectral range, across electron spin resonance quintuplet transitions observed in wurtzite-structure GaN doped with iron. Our model correctly predicts the complexity of the polarization signatures observed in the 15 independent elements of the normalized Mueller matrix for both positive and negative magnetic fields and will become useful for future analysis of frequency and magnetic field-dependent magnetic resonance measurements.

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author
; ; ; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Physical Review B
volume
110
issue
5
article number
054413
pages
18 pages
publisher
American Physical Society
external identifiers
  • scopus:85200801048
ISSN
2469-9950
DOI
10.1103/PhysRevB.110.054413
language
English
LU publication?
yes
additional info
Publisher Copyright: © 2024 authors. Published by the American Physical Society. Published by the American Physical Society under the terms of the "https://creativecommons.org/licenses/by/4.0/"Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. Funded by "https://www.kb.se/samverkan-och-utveckling/oppen-tillgang-och-bibsamkonsortiet/bibsamkonsortiet.html"Bibsam.
id
5d0d246f-5566-411d-9db9-454ff7626409
date added to LUP
2024-08-21 06:21:35
date last changed
2024-08-22 15:18:56
@article{5d0d246f-5566-411d-9db9-454ff7626409,
  abstract     = {{<p>A generalized approach derived from Bloch's equation of motion of nuclear magnetic moments is presented to model the frequency, magnetic field, spin density, and temperature dependencies in the electromagnetic permeability tensor for materials with magnetic resonances. The resulting tensor model predicts characteristic polarization signatures which can be observed, for example, in Mueller matrix element spectra measured. When augmented with thermodynamic considerations and suitable Hamiltonian description of the magnetic eigenvalue spectrum, important parameters such as density, spectral amplitude distribution, relaxation time constants, and geometrical orientation parameters of the magnetic moments can be obtained from comparing the generalized model approach to experimental data. We demonstrate our approach by comparing model calculations with full Mueller matrix element spectra measured at an oblique angle of incidence in the terahertz spectral range, across electron spin resonance quintuplet transitions observed in wurtzite-structure GaN doped with iron. Our model correctly predicts the complexity of the polarization signatures observed in the 15 independent elements of the normalized Mueller matrix for both positive and negative magnetic fields and will become useful for future analysis of frequency and magnetic field-dependent magnetic resonance measurements.</p>}},
  author       = {{Rindert, Viktor and Richter, Steffen and Kühne, Philipp and Ruder, Alexander and Darakchieva, Vanya and Schubert, Mathias}},
  issn         = {{2469-9950}},
  language     = {{eng}},
  month        = {{08}},
  number       = {{5}},
  publisher    = {{American Physical Society}},
  series       = {{Physical Review B}},
  title        = {{Bloch equations in terahertz magnetic-resonance ellipsometry}},
  url          = {{http://dx.doi.org/10.1103/PhysRevB.110.054413}},
  doi          = {{10.1103/PhysRevB.110.054413}},
  volume       = {{110}},
  year         = {{2024}},
}