Structural, electric modulus and complex impedance analysis of ZnO/TiO₂ composite ceramics

Abstract

ZnO/TiO2 composite ceramics have been prepared by solid‐state reaction technique at 900°C. The X‐ray diffraction results revealed the formation of secondary phases referred to as spinel Zn2TiO4 and hexagonal ZnTiO3. The structural analysis showed that all the composites that have been prepared have a polycrystalline nature and a hexagonal wurtzite structure. The complex modulus (M) and electric impedance of the samples have been investigated by broadband dielectric spectroscopy in a wide range of temperature (40°C‐110°C) and frequency (0.1 Hz to 10 MHz). The modulus plots (M′′, M′) illustrate the presence of non‐Debye type of relaxations attributed to the effects of interfacial and dipolar polarizations. The real and the imaginary parts of the impedance are well fitted to equivalent circuit models. At high temperatures, Z″max varies from 0.03 × 106 to 4.9 × 106 Ω when the TiO2 doping concentration increases from 1 to 7 wt%. From the obtained results, the secondary phase ZnTiO3 plays an important role in the electrical properties.

Evaluation of the Corrosion Resistance Properties of Electroplated Chitosan-Zn1−xCuxO Composite Thin Films

“…Various methods have been used to synthesize ZnO nanoparticles such as sol-gel, radio-frequency (RF) sputtering, chemical vapor deposition, pulsed laser deposition, and spray pyrolysis [ 28 , 29 , 30 , 31 , 32 ]. In addition, ZnO lattices have be shown to contain various types of defect helping them to behave as n-type semi-conductors due to zinc and oxygen vacancies and interstitials, as well as more complex defects [ 33 , 34 , 35 , 36 , 37 , 38 ]. Some research groups have modified ZnO properties through adding dopant materials such as N, Al, Ga, Cu, Mg, and In, which can significantly enhance the electrical, dielectric, and optical properties of ZnO [ 30 , 32 , 38 , 39 , 40 ].…”

Evolution of Intrinsic and Extrinsic Electron Traps at Grain Boundary during Sintering ZnO Based Varistor Ceramics

“…They are equal to the trap depth of intrinsic point defects Zn i ¨ and V O ˙, respectively [ 24 ]. In consequence, the evolution of them could be possibly characterized via fitting the ε ″ spectra by using the Cole–Cole equation [ 23 , 24 , 35 , 36 ]: where k 0 represents the magnitude of DC conductivity while k i ( i = 1, 2, 3 ...) is the magnitude of permittivity contributed by the i th relaxation (∆ ε 0 ). τ i is the relaxation time and α i is the depression angle.…”

“…They are equal to the trap depth of intrinsic point defects Zni¨ and VO˙, respectively [24]. In consequence, the evolution of them could be possibly characterized via fitting the ε″ spectra by using the Cole-Cole equation [23,24,35,36]:…”

Synthesis by Hydrothermal Treatment of ZnO-Based Varistors Doped with Rare Earth Oxides and Their Characterization by Impedance Spectroscopy

“…Due to its extraordinary electrical, dielectric and optical properties, zinc oxide (ZnO) has been used in various industrial applications, and one of the most notable applications is its use in varistor systems [1]. ZnO-based ceramic varistors are used as surge protection devices in the electronics industry and as lightning conductors in power distribution systems.…”

“…The particular performance of a ceramic varistor can be obtained from its V-I relationship. The characteristic footprint of the V-I relationship comprises three main regions: a low current region (1), a non-linearity region (2) and a pickup region (3). In region 1, known as the linear region, an ohmic behavior is observed where the current is a function of the resistivity of the grain boundaries, which is 10 orders of magnitude greater than the ZnO grain resistivity [10,11].…”