• K Guidara

Articles written in Bulletin of Materials Science

• Dielectric relaxation and ionic conductivity studies of Na2ZnP2O7

The Na2ZnP2O7 compound was obtained by the conventional solid-state reaction. The sample was characterized by X-ray powder diffraction, infrared analysis and electrical impedance spectroscopy. The impedance plots show semicircle arcs at different temperatures and an electrical equivalent circuit has been proposed to explain the impedance results. The circuits consist of the parallel combination of bulk resistance 𝑅p and constant phase elements CPE. Dielectric data were analyzed using complex electrical modulus 𝑀* for the sample at various temperatures. The frequency dependence of the conductivity is interpreted in terms of Jonscher’s law. The conductivity 𝜎d.c. follows the Arrhenius relation. The near value of activation energies obtained from the analysis of 𝑀'' and conductivity data confirms that the transport is through ion hopping mechanism, dominated by the motion of the Na+ ions in the structure of the investigated materials.

• Conductivity and dielectric studies on (Na0.4Ag0.6)2PbP2O7 compound

Electrical properties of the (Na0.4Ag0.6)2PbP2O7 compound were studied using complex impedance spectroscopy in the frequency range 200 Hz–5 MHz and temperature range (484–593 K). Combined impedance and modulus plots were used to analyse the sample behaviour as a function of frequency at different temperatures. Temperature dependence of d.c. and a.c. conductivity indicates that electrical conduction in the material is a thermally activated process. The frequency dependence of the a.c. conduction activation energy was found to obey a mathematical formula.

• A.c. conductivity and dielectric study of LiNiPO4 synthesized by solid-state method

LiNiPO4 compound was prepared by the conventional solid-state reaction. The sample was characterized by X-ray powder diffraction, infrared, Raman analysis spectroscopy and electrical impedance spectroscopy. The compound crystallizes in the orthorhombic system, space group 𝑃𝑛𝑚𝑎 with 𝑎 = 10.0252(7) Å, 𝑏 = 5.8569(5) Å and 𝑐 = 4.6758(4) Å. Vibrational analysis was used to identify the presence of PO$^{3-}_{4}$ group in this compound. The complex impedance has been measured in the temperature and frequency ranges 654–716 K and 242 Hz–5 MHz, respectively. The 𝑍' and 𝑍'' vs frequency plots are well-fitted to an equivalent circuit consisting of series of combination of grains and grain boundary elements. Dielectric data were analysed using complex electrical modulus 𝑀* for the sample at various temperatures. The modulus plots are characterized by the presence of two peaks thermally activated. The frequency dependence of the conductivity is interpreted in terms of equation: 𝜎_a.c.(𝜔) = [𝜎g/(1 + 𝜏2𝜔2) + (𝜎𝜏2𝜔2/1 + 𝜏2𝜔2) + A𝜔n]. The near values of activation energies obtained from the analysis of 𝑀", conductivity data and equivalent circuit confirms that the transport is through ion hopping mechanism dominated by the motion of Li+ in the structure of the investigated material.

• # Bulletin of Materials Science

Volume 44, 2021
All articles
Continuous Article Publishing mode

• # Dr Shanti Swarup Bhatnagar for Science and Technology

Posted on October 12, 2020

Prof. Subi Jacob George — Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bengaluru
Chemical Sciences 2020

Physical Sciences 2020

• # Editorial Note on Continuous Article Publication

Posted on July 25, 2019