مشخصات پژوهش

Dispersion of ferroelectric- and ferromagnetic nanoparticles in liquid crystals (LCs) is investigated in the last decades. Recently, doping multiferroic-BiFeO3 nanoparticles in the LCs has become of interest. These nanoparticles have coupled ferroelectric- and ferromagnetic properties at ambient temperature. In the present experiments, a nematic LC was doped with a low concentration of BiFeO3 nanoparticles, synthesized using a modified Pechini method. The particles were characterized and their dispersions in heptane with an added surfactant were used for doping of the LC. The measured dielectric constants in the doped LCs varied as compared to the pure LC. It was shown that the presence of a magnetic field in the cooling process (cooling down from isotropic to anisotropic phase) of the LC cells leads to a significant increase of dielectric anisotropy. Also, the transition temperature decreased in the nematic-isotropic transition temperature for the doped sample.