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%.

摘要

我们研究了两种类型的纳米颗粒，磁性（γFe的冲击₂ ö ₃）和非磁性单（的CeO ₂分散在向列型5CB矩阵）。介电谱用于研究两种纳米粒子掺杂的向列型5CB的介电性能。通过将合适的等效电路模型拟合到实验数据，我们显示了在本体中以及在向列-电极界面上，向列的电物理参数的变化。发现随着纳米粒子浓度的增加，阻抗模量减小。这种增加归因于电导率的增加，这与移动电荷载流子在电极附近积累有关。对于非磁性纳米粒子，两者的扩散常数$d$ 和流动性 $\mu$随着浓度的增加而增加。令人惊讶的是，对于磁性纳米粒子，$d$ 和 $\mu$ 浓度大于3％时会显着下降。