Study of Structural Changes in Nematic Liquid Crystals Doped with Magnetic Nanoparticles Using Surface Acoustic Waves
The surface acoustic waves (SAWs) were used to study the effect of magnetic nanoparticles on nematic liquid crystal (NLC) behavior in weak magnetic and electric fields. The measurement of the attenuation of SAW propagating along the interface between piezoelectric substrate and liquid crystal is sho...
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MDPI AG
2020-11-01
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| Series: | Crystals |
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| Online Access: | https://www.mdpi.com/2073-4352/10/11/1023 |
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| author | Peter Bury Marek Veveričík František Černobila Peter Kopčanský Milan Timko Vlasta Závišová |
| author_facet | Peter Bury Marek Veveričík František Černobila Peter Kopčanský Milan Timko Vlasta Závišová |
| author_sort | Peter Bury |
| collection | DOAJ |
| description | The surface acoustic waves (SAWs) were used to study the effect of magnetic nanoparticles on nematic liquid crystal (NLC) behavior in weak magnetic and electric fields. The measurement of the attenuation of SAW propagating along the interface between piezoelectric substrate and liquid crystal is showed as an effective tool to study processes of structural changes. The magnetic nanoparticles Fe<sub>3</sub>O<sub>4</sub> of nanorod shape and different low volume concentration were added to the NLC (4-(trans-4′-n-hexylcyclohexyl)-isothiocyanatobenzene (6CHBT)) during its isotropic phase. In contrast to undoped liquid crystals the distinctive different SAW attenuation responses induced by both magnetic and also electric fields in studied NLC samples were observed suggesting both structural changes and the orientational coupling between both magnetic and electric moments of nanoparticles and the director of the NLC molecules. Experimental measurements including the investigation under linearly increasing and/or jumped magnetic and electrical fields, respectively, as well as the investigation of temperature and time influences on structural changes were done. The investigation of the SAW anisotropy gives supplemental information about the internal structure of nanoparticles in investigated NLCs. In addition, some magneto-optical investigations were performed to support SAW results and study their stability and switching time. The analysis of observed SAW attenuation characteristics confirmed the role of concentration of magnetic nanoparticles on the resultant behavior of investigated NLC compounds. Obtained results are discussed within the context of previous ones. The theoretical background of the presented SAW investigation is introduced, too. |
| first_indexed | 2024-03-10T14:58:55Z |
| format | Article |
| id | doaj.art-79513c86247647b48c09c33a28822a6f |
| institution | Directory Open Access Journal |
| issn | 2073-4352 |
| language | English |
| last_indexed | 2024-03-10T14:58:55Z |
| publishDate | 2020-11-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Crystals |
| spelling | doaj.art-79513c86247647b48c09c33a28822a6f2023-11-20T20:22:13ZengMDPI AGCrystals2073-43522020-11-011011102310.3390/cryst10111023Study of Structural Changes in Nematic Liquid Crystals Doped with Magnetic Nanoparticles Using Surface Acoustic WavesPeter Bury0Marek Veveričík1František Černobila2Peter Kopčanský3Milan Timko4Vlasta Závišová5Department of Physics, FEIT, Žilina University, Univerzitná 1, 01026 Žilina, SlovakiaDepartment of Physics, FEIT, Žilina University, Univerzitná 1, 01026 Žilina, SlovakiaDepartment of Physics, FEIT, Žilina University, Univerzitná 1, 01026 Žilina, SlovakiaInstitute of Experimental Physics, Slovak Academy of Sciences, Watsonova 47, 04001 Košice, SlovakiaInstitute of Experimental Physics, Slovak Academy of Sciences, Watsonova 47, 04001 Košice, SlovakiaInstitute of Experimental Physics, Slovak Academy of Sciences, Watsonova 47, 04001 Košice, SlovakiaThe surface acoustic waves (SAWs) were used to study the effect of magnetic nanoparticles on nematic liquid crystal (NLC) behavior in weak magnetic and electric fields. The measurement of the attenuation of SAW propagating along the interface between piezoelectric substrate and liquid crystal is showed as an effective tool to study processes of structural changes. The magnetic nanoparticles Fe<sub>3</sub>O<sub>4</sub> of nanorod shape and different low volume concentration were added to the NLC (4-(trans-4′-n-hexylcyclohexyl)-isothiocyanatobenzene (6CHBT)) during its isotropic phase. In contrast to undoped liquid crystals the distinctive different SAW attenuation responses induced by both magnetic and also electric fields in studied NLC samples were observed suggesting both structural changes and the orientational coupling between both magnetic and electric moments of nanoparticles and the director of the NLC molecules. Experimental measurements including the investigation under linearly increasing and/or jumped magnetic and electrical fields, respectively, as well as the investigation of temperature and time influences on structural changes were done. The investigation of the SAW anisotropy gives supplemental information about the internal structure of nanoparticles in investigated NLCs. In addition, some magneto-optical investigations were performed to support SAW results and study their stability and switching time. The analysis of observed SAW attenuation characteristics confirmed the role of concentration of magnetic nanoparticles on the resultant behavior of investigated NLC compounds. Obtained results are discussed within the context of previous ones. The theoretical background of the presented SAW investigation is introduced, too.https://www.mdpi.com/2073-4352/10/11/1023ferronematicsstructural changessurface acoustic waves |
| spellingShingle | Peter Bury Marek Veveričík František Černobila Peter Kopčanský Milan Timko Vlasta Závišová Study of Structural Changes in Nematic Liquid Crystals Doped with Magnetic Nanoparticles Using Surface Acoustic Waves Crystals ferronematics structural changes surface acoustic waves |
| title | Study of Structural Changes in Nematic Liquid Crystals Doped with Magnetic Nanoparticles Using Surface Acoustic Waves |
| title_full | Study of Structural Changes in Nematic Liquid Crystals Doped with Magnetic Nanoparticles Using Surface Acoustic Waves |
| title_fullStr | Study of Structural Changes in Nematic Liquid Crystals Doped with Magnetic Nanoparticles Using Surface Acoustic Waves |
| title_full_unstemmed | Study of Structural Changes in Nematic Liquid Crystals Doped with Magnetic Nanoparticles Using Surface Acoustic Waves |
| title_short | Study of Structural Changes in Nematic Liquid Crystals Doped with Magnetic Nanoparticles Using Surface Acoustic Waves |
| title_sort | study of structural changes in nematic liquid crystals doped with magnetic nanoparticles using surface acoustic waves |
| topic | ferronematics structural changes surface acoustic waves |
| url | https://www.mdpi.com/2073-4352/10/11/1023 |
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