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Jafar Poursamad Bonab

Jafar Poursamad Bonab

Academic rank: Associate Professor
ORCID:
Education: PhD.
ScopusId:
HIndex: 0/00
Faculty: Faculty of Basic Sciences
Address:
Phone: 04137745000-1643

Research

Title
Controlling the dielectric constant values of nematic liquid crystals using ferroelectric and multiferroic nanoparticles
Type
JournalPaper
Keywords
Liquid Crystal, Nano particle
Year
2024
Journal Optical Materials
DOI
Researchers Maryam Beygmohamadi ، Jafar Poursamad Bonab ، Mahsa Khadem Sedigh

Abstract

Notably, the simultaneous manifestation of ferromagnetic and ferroelectric properties at ambient temperature has spurred significant interest in incorporating multiferroic bismuth ferrite nanoparticles (BiFeO3) into liquid crystal matrices. In this study, the parallel and perpendicular dielectric components (ε‖ and ε⊥) and dielectric anisotropy (△ε = ε‖ − ε⊥) of two different nanoparticles, barium titanate (BaTiO3) and BiFeO3, doped into E7, were measured at various temperatures and frequencies. Nematic mixture E7, a widely utilized nematic liquid crystal in research and display technologies, is a eutectic mixture composed of four cyanobiphenyl derivatives i.e. 5CB, 7CB, 8OCB, and 5CT. The findings indicate a substantial reduction in dielectric anisotropy upon introducing nanoparticles into the nematic liquid crystal environment. This research highlights the significant influence of barium titanate nanoparticles, which are smaller (approximately 12 nm), on the dielectric constant. This effect was analyzed based on varying concentrations and compared to a nanoparticle with ferroic properties. Moreover, the dielectric constant can be modulated through an alternative approach. Specifically, applying an electric field during the filling process of liquid crystal cells leads to changes in the dielectric constant. These changes, observed for both nanoparticles, were particularly evident at a precise concentration of 0.1 wt%, resulting in a decreased dielectric constant.