Effective infrared reﬂectivity and dielectric function of polycrystalline alumina ceramics

Result code in IS VaVaI
<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216305%3A26620%2F17%3APU123921" target="_blank" >RIV/00216305:26620/17:PU123921 - isvavai.cz</a>
Result on the web
<a href="https://onlinelibrary.wiley.com/doi/full/10.1002/pssb.201600607" target="_blank" >https://onlinelibrary.wiley.com/doi/full/10.1002/pssb.201600607</a>
DOI - Digital Object Identifier
<a href="http://dx.doi.org/10.1002/pssb.201600607" target="_blank" >10.1002/pssb.201600607</a>

Result language
angličtina
Original language name
Effective infrared reﬂectivity and dielectric function of polycrystalline alumina ceramics
Original language description
Room-temperature infrared (IR) reflectivity, terahertz transmission and evaluated effective complex dielectric response of four polycrystalline alumina ceramics (corundum) with highly anisotropic grains in the IR range were determined. The spectra were compared with modelled spectra based on the known IR response of sapphire single crystal and Bruggeman and Lichtenecker models of the effective medium approximation (EMA). The results are extremely sensitive to the surface treatment (polishing), but do not depend on the grain size in the range of approximate to 0.3-1m and on the weak doping, needed for processing of optically transparent ceramics. As all the samples show similar grain shapes and topology, no measurable differences among the fully dense samples were observed. Agreement with the modelled spectra is reasonable, but shows a higher effective mode damping. A weak geometrical resonance was revealed near 500cm(-1), better described by the Bruggeman model. The small sample porosity up to 6.2% is revealed mainly as a reduced reflectivity above approximate to 650cm(-1), which produces weak losses in the high-frequency range above the TO phonon modes, better described by the Lichtenecker model.
Czech name
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Czech description
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Type
J<sub>imp</sub> - Article in a specialist periodical, which is included in the Web of Science database
CEP classification
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OECD FORD branch
10302 - Condensed matter physics (including formerly solid state physics, supercond.)

Project
<a href="/en/project/LQ1601" target="_blank" >LQ1601: CEITEC 2020</a><br>
Continuities
P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Publication year
2017
Confidentiality
S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

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