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The effect of magnetic nanoparticles upon the smectic-A to smectic-C* phase transition |
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| Authors: | George Cordoyiannis Sašo Gyergyek Brigita Rožič Samo Kralj Zdravko Kutnjak George Nounesis |
| Affiliation: | 1. Department of Physics, National and Kapodistrian University of Athens, Zografou, Greece;2. Condensed Matter Physics Department, Jo?ef Stefan Institute, Ljubljana, Slovenia;3. Biomolecular Physics Laboratory, National Centre for Scientific Research ‘Demokritos’, Aghia Paraskevi, Greecegeorge.cordoyiannis@ijs.si;5. Department for Materials Synthesis, Jo?ef Stefan Institute, Ljubljana, Slovenia;6. Condensed Matter Physics Department, Jo?ef Stefan Institute, Ljubljana, Slovenia;7. Faculty of Natural Sciences and Mathematics, University of Maribor, Maribor, Slovenia;8. Jo?ef Stefan International Postgraduate School, Ljubljana, Slovenia;9. Biomolecular Physics Laboratory, National Centre for Scientific Research ‘Demokritos’, Aghia Paraskevi, Greece |
| Abstract: | We report on wide-angle X-ray scattering measurements along the smectic-A to chiral ferroelectric smectic-C* phase transition of the liquid crystal SCE9 and its mixture with maghemite magnetic nanoparticles of typical dimension 20 nm. The temperature profiles of the tilt angle are fitted by an extended mean-field model. Neither pre-transitional order effects nor variations in the SmA layer thickness are observed, indicating a rather negligible influence of these nanoparticles upon the molecular orientation at the smectic-A to smectic-C* phase transition of SCE9. These results are very different from what was observed for smaller CdSe nanoparticles (3.5 nm) where both a dilation of the smectic layers in the SmA phase and a crossover behaviour for the smectic-A to smectic-C* transition away from tricriticality have been observed for analogous concentrations. |
| Keywords: | Magnetic nanoparticles X-ray scattering smectic liquid crystals |