Dielectric spectroscopy study on the impact of magnetic and nonmagnetic nanoparticles dispersion on ionic behavior in nematic liquid crystal

ABSTRACT

We investigated the impact of two types of nanoparticles, magnetic (γFe₂O₃) and nonmagnetic one (CeO₂) dispersed in nematic 5CB matrix. Dielectric spectroscopy was used to investigate the dielectric behavior of the nematic 5CB doped by both kinds of nanoparticles. By fitting a suitable equivalent electric circuit model to the experimental data we show the change of electro–physical parameters of the nematic in the bulk and at the nematic–electrode interface. It is found that the impedance modulus decreases with increasing the concentration of nanoparticles. This increase is attributed to an increase of the conductivity, which is related to the mobile charge carriers accumulating near the electrodes. For nonmagnetic nanoparticles, both the diffusion constant $D$ and the mobility $\mu$ were increased with increasing concentration. Surprisingly, for magnetic nanoparticles, the increase of $D$ and $\mu$ is followed by a considerable decrease at concentration higher than 3%.

KEYWORDS:

• Liquid crystal
• nanoparticles
• dielectric spectroscopy
• equivalent electric circuit

Acknowledgement

We acknowledge Jerome FRESNAIS of PHENIX laboratory Sorbonne Universités France, for providing magnetic (γFe₂O₃) and nonmagnetic (CeO₂) nanoparticles.

Disclosure statement

No potential conflict of interest was reported by the author(s).