Structural, dielectric and impedance studies on high-k ZrO_2-TiO_2 nanocomposite

摘要

High-k dielectric ZrO_2-TiO_2 nanocomposite was prepared using a simple Coprecipitation-calcination technique. X-ray diffraction shows that the synthesized nanocomposite showed monoclinic structure for ZrO_2 and orthorhombic structure for TiO_2. The SEM and TEM images show an average particle size of 20-30 nm. The dielectric properties of ZrO_2-TiO_2 nanoparticles were studied in the frequency range of 50 Hz-5 MHz at different temperatures. The dielectric constant and dielectric loss is found to decrease with an increase in the frequency at different temperatures. The dielectric properties of ZrO_2-TiO_2 nanoparticles are found to be significantly enhanced specially in the low frequency range due to confinement. The dielectric constant was found to greater than that of nano zirconia. The AC electrical conductivity measurements reveal that the conduction depends on both the frequency and the temperatures. Nyquist plots indicated the presence of a non-Debye relaxation. The determined relaxation times followed Arrhenius law and the activation energy for relaxation was found to be 0.178 eV.