The [Fe.sub.3][O.sub.4] nanoparticle doping effect in liquid crystal on electrical and dielectric properties

[Fe.sub.3][O.sub.4] nanoparticles were doped into E63 coded liquid crystal (LC) with 0.1 wt% to investigate the effect of [Fe.sub.3][O.sub.4] on the electrical and dielectric properties of LC in a wide range of frequency, bias voltage, and illumination. The frequency, bias voltage, and illumination level dependence of the electrical and dielectric properties of pure E63 and doped mixture (E63- [Fe.sub.3][O.sub.4]) has been investigated using the current-voltage (I-V) and admittance spectroscopy (C-V and G/ω-V) data in the frequency range of 10 kHz -1 MHz at room temperature. Results show that the increment in current with [Fe.sub.3][O.sub.4] doping is due to the metallic nature of the [Fe.sub.3][O.sub.4] nanoparticles. The current switching voltage of reorientation is shifted to lower voltage values as a result of [Fe.sub.3][O.sub.4] doping. Same behavior is also observed with increasing illumination level. The polarization contribution of [Fe.sub.3][O.sub.4] doping is evident considering the values of [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII] at low frequencies. Moreover, depending on the existence of [Fe.sub.3][O.sub.4] doping agent, there is a split in [σ.sub.ac]-f plots where [σ.sub.ac] values increase with frequency, especially at high frequencies. PACS Nos.: 77.84.Nh, 77.22.Ej, 64.70.M-, 77.84.-s. Nous dopons un cristal liquide (LC) E63 avec des nanoparticules de [Fe.sub.3][O.sub.4] a 0.1% en poids, afin d'etudier l'effet du Fe2O4 sur les proprietes electriques et dielectriques du LC, sur un large domaine de frequence, de tension de polarisation et d'illumination. Nous utilisons la relation courant-voltage (I-V) et les donnees de spectroscopie d'admittance (C-Vet G/ω-V) dans le domaine de frequence de 10 kHz a 1 MHz a la temperature de la piece, afin de determiner la dependance des proprietes electriques et dielectriques du E63 pur et du melange (E63-[Fe.sub.3][O.sub.4]) sur la frequence, la tension de polarisation et l'illumination. Les resultats montrent que l'augmentation du courant avec le dopage en [Fe.sub.3][O.sub.4] est due au caractere metallique des nanoparticules de [Fe.sub.3][O.sub.4]. Le voltage de commutation de reorientation est deplace vers de plus faibles voltages suite au dopage avec [Fe.sub.3][O.sub.4]. Le meme comportement est observe avec l'augmentation du niveau d'illumination. La contribution a la polarisation du [Fe.sub.3][O.sub.4] est evidente, considerant les valeurs de [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII] a basse frequence. De plus, selon l'existence de l'agent dopant [Fe.sub.3][O.sub.4], il y a une brisure dans les graphiques [σ.sub.ac]-f, ou les valeurs de [σ.sub.ac] augmentent avec la frequence, surtout a haute frequence. [Traduit par la Redaction]
1. Introduction Liquid crystal (LC) materials have attracted the attention of researchers over the last few decades [1-11]. In recent years, LCs have proven to be a promising material owing [...]