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We report on terahertz (THz) electron paramagnetic resonance generalized spectroscopic ellipsometry (THz-EPR-GSE). Measurements of field and frequency dependencies of magnetic response due to spin transitions associated with nitrogen defects in 4H-SiC are shown as an example. THz-EPR-GSE dispenses with the need of a cavity, permits independently scanning field and frequency parameters, and does not require field or frequency modulation. We investigate spin transitions of hexagonal ( h) and cubic ( k) coordinated nitrogen including coupling with its nuclear spin (I = 1), and we propose a model approach for the magnetic susceptibility to account for the spin transitions. From the THz-EPR-GSE measurements, we can fully determine polarization properties of the spin transitions, and we can obtain the k coordinated nitrogen g and hyperfine splitting parameters using magnetic field and frequency dependent Lorentzian oscillator line shape functions. Magnetic-field line broadening presently obscures access to h parameters. We show that measurements of THz-EPR-GSE at positive and negative fields differ fundamentally and hence provide additional information. We propose frequency-scanning THz-EPR-GSE as a versatile method to study properties of spins in solid state materials.
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The Dobryakov–Lebedev Relation Extended to Partially Resolved EPR Spectra
The Dobryakov–Lebedev relation (Sov Phys Doklady 13:873, 1969), which relates the line width of the first-derivative of a Gaussian–Lorentzian convolution to the line widths of its Gaussian and Lorentzian components for an unresolved EPR line, is extended to resolved lines. Applying this extension to nitroxide-free radicals in solutions of low-viscosity solvents offers an opportunity to study interactions of the spins with the microwave field and spin–spin interactions previously inaccessible except by tedious numerical methods.
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- PAR ID:
- 10329239
- Date Published:
- Journal Name:
- Applied Magnetic Resonance
- ISSN:
- 0937-9347
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1007/s00723-021-01433-z
