Characterization of Electrical Behavior of Ba<sub>5</sub>HoTi<sub>3</sub>V<sub>7</sub>O<sub>30</sub> Ceramic Using Impedance Analysis

Abstract

Polycrystalline sample of Ba5HoTi3V7O30 was prepared using solid-state reaction technique. X-ray structural analysis indicated a single-phase formation with orthorhombic structure. Microstructural study by SEM showed non-uniform distribution of grains over the surface of the sample. Impedance and modulus spectroscopy studies were carried out, as functions of frequency (42 Hz - 5 MHz) and temperature (RT-773K). The Nyquist plots clearly showed the presence of both bulk and grain boundary effect in the compound. Electrical phenomena in the material can appropriately be modeled in terms of an equivalent circuit with R, C and CPE in parallel. The fitting procedure used here allows us to determine the value of R and C with good precision. Here R2 and R3 correspond to the resistance contributed from the grain boundary and bulk, respectively. C1 and C2 correspond to the capacitance contributed from the grain boundary and bulk, respectively. The real part of electrical modulus shows that the material is highly capacitive. The asymmetric peak of the imaginary part of electric modulus M″, predicts a non Debye type relaxation. The activation energy of the compound (calculated both from impedance and modulus spectrum) is same, and hence the relaxation process may be attributed to the same type of charge carriers

Characterization and charge transport properties of sodium ion conducting PEO:NaBr solid polymer electrolyte films

“…This decrease in crystallinity is due to the random dissociation or dispersion of dopant into the polymer matrix, hence amorphous phase increased which is observed in SEM results. In the amorphous phase flexibility of polymeric backbone is more which increases migration of ions through inter/intra chain polymer segments and facilitates higher mobility of the charge carriers 38 . Due to the dissociation of dopant more number of free ions transferred into the polymer electrolyte hence ionic conductivity increases with dopant concentration.…”

“…In the amorphous phase flexibility of polymeric backbone is more which increases migration of ions through inter/ intra chain polymer segments and facilitates higher mobility of the charge carriers. 38 Due to the dissociation of dopant more number of free ions transferred into the polymer electrolyte hence ionic conductivity increases with dopant concentration. From the impedance data relaxation time of pure PEO and NaBr/PEO electrolytes have been determined.…”

Dielectric and Electric Properties of Ba0.996La0.004Ti0.999O3 Ceramics Doped with Europium and Hafnium Ions

“…This was reflected in the high values of the chi-square test χ 2 (~10 −3 ). The equivalent circuit underwent a modification, which was used by many authors, in the compounds based on BaTiO 3 [24,33], and for other ceramics materials, in which the crystalline structure was significantly different from classical perovskites [34,35]. Namely, two capacitors in the RC circuits were replaced with constant phase elements (CPE1 and CPE2) (Figure 11).…”