Optical phonon modes and infrared dielectric properties of monoclinic CoWO 4 microcrystals.

Registro completo de metadados
MetadadosDescriçãoIdioma
Autor(es): dc.creatorMoreira, Roberto Luiz-
Autor(es): dc.creatorAlmeida, Rafael Mendonça-
Autor(es): dc.creatorSiqueira, Kisla Prislen Félix-
Autor(es): dc.creatorAbreu, Cíntia Grossi de-
Autor(es): dc.creatorDias, Anderson-
Data de aceite: dc.date.accessioned2025-08-21T15:04:45Z-
Data de disponibilização: dc.date.available2025-08-21T15:04:45Z-
Data de envio: dc.date.issued2017-08-08-
Data de envio: dc.date.issued2017-08-08-
Data de envio: dc.date.issued2016-
Fonte completa do material: dc.identifierhttp://www.repositorio.ufop.br/handle/123456789/8464-
Fonte completa do material: dc.identifierhttp://iopscience.iop.org/article/10.1088/0022-3727/49/4/045305/pdf-
Fonte completa do material: dc.identifierhttp://dx.doi.org/10.1088/0022-3727/49/4/045305-
Fonte: dc.identifier.urihttp://educapes.capes.gov.br/handle/capes/1002038-
Descrição: dc.descriptionThe phonon characteristics of CoWO4 microcrystals with monoclinic Wolframite structure were investigated by far-infrared (IR) and Raman spectroscopies. Near-normal spectra were taken for IR light polarization along the principal b-axis (Au modes) and along several angles within the ac-plane (Bu modes). The IR spectra were analyzed with a generalized Drude– Lorentz model, and all predicted polar phonon modes were fully determined, including their symmetries, the dielectric Lorentz parameters and the non-orthogonal phonon polarizations for the Bu modes. Anomalous dispersion and negative values for the real and imaginary parts of the off-diagonal components of the dielectric tensor functions were identified and discussed under the light of the varying phonon polarization directions (spread out in the ac-plane). The obtained static and background dielectric tensors gave an average permittivity of 16.1 (at microwave region), refractive indices along the principal dielectric axes of 2.22, 2.33 and 2.44 (at 1 μm), the optical axes, and an estimated value for the biaxial angle of the crystal. Polarized Raman spectra on appropriate scattering configurations revealed the 18 non-polar gerade phonons of CoWO4 crystals, with their correct symmetries attributed.-
Formato: dc.formatapplication/pdf-
Idioma: dc.languageen-
Direitos: dc.rightsrestrito-
Palavras-chave: dc.subjectInfrared spectroscopy-
Palavras-chave: dc.subjectMonoclinic crystals-
Palavras-chave: dc.subjectMultiferroics-
Palavras-chave: dc.subjectRaman scattering-
Título: dc.titleOptical phonon modes and infrared dielectric properties of monoclinic CoWO 4 microcrystals.-
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