Abstract
Zn and Cu were incorporated into bentonite matrix to form composites with concentration 5 wt%. The prepared samples were characterized via X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX). XRD studies illustrated that the addition of Zn and Cu into bentonite increases the grain size and crystallinity. The morphological analysis indicated significant changes in the composites. Uniform distribution of Zn is observed, whereas the distribution of Cu is non-uniform on the bentonite surface. EDX pattern confirmed the presence of Zn and Cu in the doped samples. The dielectric response was investigated in the frequency range of 1–300 kHz at different temperatures. Adding Zn and Cu reduced the dielectric constant and dielectric loss. Dielectric performance is associated firmly with the microstructure of material, thus the Cu-BT composite showed the lowest value which could be ascribed to the heterogeneous distribution of Cu and the largest grain size. The ac conductivity, σ’, spectra follow Jonscher’s power law. The frequency exponent was estimated from fitting the σ’ data and was found to be greater than 1 indicating that the well-localized hopping and/or reorientational motion is responsible for the conduction process. The conduction mechanism was explained based on the Jump Relaxation Model. The low dielectric loss and the frequency stability of dielectric constant make Cu-BT composite a potential candidate for capacitor application at high frequencies.