Static and dynamic dielectric effects in the vicinity of the isotropic to nematic phase transition in 7CB

Static and dynamic dielectric measurements were performed with very high accuracy on a mesogenic compound n-heptylcyanobiphenyl (7CB) in the isotropic (I) and nematic (N) phases. The critical-like temperature behaviour of the static permittivity of isotropic 7CB in the vicinity of the I-N phase tran...

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Bibliographic Details
Published inLiquid crystals Vol. 32; no. 5; pp. 625 - 631
Main Authors Ginovska, M., Czechowski, G., Déjardin, J.-L., Jadżyn, J., Hellemans, L.
Format Journal Article
LanguageEnglish
Published Taylor & Francis Group 01.05.2005
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Summary:Static and dynamic dielectric measurements were performed with very high accuracy on a mesogenic compound n-heptylcyanobiphenyl (7CB) in the isotropic (I) and nematic (N) phases. The critical-like temperature behaviour of the static permittivity of isotropic 7CB in the vicinity of the I-N phase transition can be described with the critical exponent close to 0.5, indicating the tricritical nature of the transition. Anomalously slow rotational diffusion (subdiffusion), characterized by a fractal value of the diffusion exponent α, is observed in the vicinity of the I-N transition with a lambda-like profile of the exponent temperature dependence.
ISSN:0267-8292
1366-5855
DOI:10.1080/02678290500116946