Submillimeter dielectric spectra of SC(NH2)2 and BaMnF4 single crystals
- 1 August 1982
- journal article
- research article
- Published by Taylor & Francis in Ferroelectrics
- Vol. 45 (1) , 157-162
- https://doi.org/10.1080/00150198208202010
Abstract
The dielectric spectra of thiourea and BaMnF4 were determined in all phases (85-300 K) in the 3-30 cm-1 region using the monochromatic spectrometer with tunable oscillator. Moreover, far infrared (30-450 cm-1) reflectivity of BaMnF4 at 90 and 300 K was measured and evaluated to obtain the dielectric spectra. In the case of thiourea a new extra mode near 7 cm-1 was observed in the paraelectric region. A rather complex dielectric dispersion was found in incommensurate phases in qualitative accord with theoretical expectations. In the case of BaMnF4, two low-frequency modes which partially soften at Tc were found in agreement with recent Raman results.Keywords
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