Dielectric and electrical properties of Na2Pb2La2W2Ti4Ta4O30 electroceramics

Abstract

Abstract:The polycrystalline sample of complex tungsten-bronze type compound (Na 2 Pb 2 La 2 W 2 Ti 4 Ta 4 O 30 ) was prepared by a high-temperature solid-state reaction technique. Room temperature preliminary structural study using X-ray diffraction (XRD) data exhibits the formation of a single-phase new compound. The SEM micrograph of the compound exhibits non uniform rectangular grains distributed throughout the sample surface. Detailed studies of dielectric parameters (ε r , tan δ) as a function of temperature and frequency, and P-E hysteresis (spontaneous polarization) confirmed the existence of ferroelectricity in the material. Complex impedance spectroscopy analysis, carried out as a function of frequency at different temperatures, established a correlation between the microstructure and electrical properties of the material. The electrical relaxation process occurring in the material is temperature dependent. The activation energy found from the Arrhenius plot that the conduction process in the material is of mixed type. The nature of frequency dependence of ac conductivity suggests that the material obeys Jonscher's universal power law.

Study of the structural, electrical, dielectric properties and transport mechanisms of Cu0.5Fe2.5O4 ferrite nanoparticles for energy storage, photocatalytic and microelectronic applications

“…It is clear that the frequency of these peaks shifts towards the high frequencies and that their heights decrease with increasing temperature, which demonstrates that the charge carriers involved in electrical conduction are thermally activated and confirms the semiconducting nature of this sample [ 71 , 72 ]. This behaviour is in agreement with that previously reported in the literature for different ferrite systems [ 67 , 73 ]. In the high frequency region, the convergence of the Z″ (f) spectra over the whole temperature range confirms the presence of space charges in this compound [ 68 ].…”

Nanostructured Lead Sulphide Depositions by AACVD Technique Using Bis(Isobutyldithiophosphinato)Lead(II) Complex as Single Source Precursor and Its Impedance Study

“…'A' is the pre-exponential factor and n is the frequency exponent which describes the degree of interaction of mobile charges with the lattice. Values of 'n' less than 1 corresponded to translational motion of charge carriers, while 'n' values greater than one indicated the localized hopping mechanism [34]. Values of n1 and n2 for regions I and region II were 0.85 and 0.65, respectively.…”

Giant dielectric response in microwave processed CaCu3Ti4O12 ceramics: A correlation among microstructure, dielectric and impedance properties

“…If Z ′ axis contains the centre of a semicircular arc, then the phenomenon is associated with the single relaxation time and known as Debye-type relaxation [32,33]. When the centres are below the real axis, there is distribution of the relaxation time known as non-Debye-type relaxation [34]. The non-zero intercept at high frequency region corresponds to grain response and low-frequency arc represents grain-boundary response [24].…”