Magneto-Optical Properties of a Ferronematic Colloid

Abstract

Fabrication of a thermotropic ferronematic colloid is reported, consisting of a 1% concentration of magnetite nanorods dispersed in a commercially obtained liquid crystal (LC). To produce the nanorods, solvothermal synthesis was utilized by adding Fe(CO) 5 to a reaction solution of hexadecylamine and oleic acid in n-octanol. The procedure allows for tailoring of the size and shape of the nanorods. The magnetic nanorods were functionalized with oleic acid. Magneto-optic and electro-optic properties of the colloid were characterized. Specifically, static measurements were performed to determine the birefringence and magnetic and electric Freedericksz thresholds. From the dynamic measurements, the switching time was determined. The nanorods increased the effective magnetic anisotropy of the LC. Depending on nanorod dimensions, the colloid demonstrated faster switching speeds, especially in the presence of crossed electric and magnetic fields.

Dynamic behavior of a nematic liquid crystal with added carbon nanotubes in an electric field

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Dynamic behavior of a nematic liquid crystal mixed with CoFe2O4 ferromagnetic nanoparticles in a magnetic field

“…The unique properties of nanoparticles open new development directions not only in materials science, but also in electronics, providing considerable improvement [ 13 ]. Liquid crystals, largely used for displays, are now mixed with nanoparticles such as magnetite, carbon nanotubes and quantum dots [ 14 – 22 ], yielding modified optical properties [ 23 – 25 ]. The main advantages of nanoparticles are given by their small dimensions and unique physical properties that strongly affect the local nematic order [ 26 ].…”