Govind Reddy.Y; Sadananda Chary.A; Awasti. A.M; Narender Reddy.S
Abstract
The composite solid electrolyte systems, (1-x)Pb(NO3)2:xCeO2 (x= 0, 0.02, 0.03, 0.04, 0.05 and 0.08), have been investigated by XRD for structural properties, SEM with EDS for morphological studies and Electrical properties through impedance spectroscopy. The frequency and temperature dependence of ac ...
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The composite solid electrolyte systems, (1-x)Pb(NO3)2:xCeO2 (x= 0, 0.02, 0.03, 0.04, 0.05 and 0.08), have been investigated by XRD for structural properties, SEM with EDS for morphological studies and Electrical properties through impedance spectroscopy. The frequency and temperature dependence of ac conductivity, dielectric constant and dielectric loss were measured between the temperatures 30oC to 340oC in the frequency range 1Hz to 10MHz. The complex impedance data is analyzed in conductivity, permittivity and electric modulus formalism in order to through light on transport mechanism. Variation of ac conductivity against frequency suggests the response obeying universal power law. The dynamics of conducting ion is studied through Jonscher’s Universal power law. The parameters of n and A of Jonscher’s Universal law suggest these values are strongly temperature sensitive. The variation of dielectric permittivity, loss, and modulus spectra were found to be consistent with conductivity. Impedance, dielectric and modulus analysis had indicated the non-Debye behavior in these composites. The relaxation phenomena were observed in all formalisms. Copyright © 2017 VBRI Press.
Trilok K. Pathak; L. P. Purohit
Abstract
ZnO and ZnO:N thin films were deposited on plane glass substrate using RF sputtering method. The crystalline structure and surface morphology of the film was investigated using XRD and SEM. The XRD patterns of ZnO thin films have largest crystalline orientation for the (002) peak and shows wurtzite structure. ...
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ZnO and ZnO:N thin films were deposited on plane glass substrate using RF sputtering method. The crystalline structure and surface morphology of the film was investigated using XRD and SEM. The XRD patterns of ZnO thin films have largest crystalline orientation for the (002) peak and shows wurtzite structure. The ZnO thin films composed of dance packing, grains without any cracks indicating uniform grain size distribution. The transmittance and absorbance of ZnO thin film was measured using UV-VIS-IR spectrophotometer in the wavelength range 200 nm-800 nm. The band gap of ZnO film was3.26 eV calculated by Tauc’s plot method. Photoluminescence property was also investigated at the excitation wavelength 325 nm. A.C. conductivity measurements carried out on the ZnO/ZnO:N thin films at room temperature in the frequency range 10 KHz to 0. 1MHz. This measurement also helps to distinguish between localized and free band conduction.The study demonstrated that ZnO and ZnO:N thin films fabricated by RF sputtering method can be used in electronicand optoelectronic applications due to high transmittance in visible region, large bandgap and localized conduction. Copyright © 2016 VBRI Press.
Pragya Pandit; Pargin Bangotra
Abstract
In this paper we investigate the effect of lanthanum doping on structural, dielectric and electrical properties of lead magnesium niobate - lead titanate, 0.65Pb(Mg1/3Nb2/3O3)- 0.35PbTiO3 (x=0, 0.02, 0.05) ferroelectric ceramics. Dielectric and AC impedance spectroscopic measurements were ...
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In this paper we investigate the effect of lanthanum doping on structural, dielectric and electrical properties of lead magnesium niobate - lead titanate, 0.65Pb(Mg1/3Nb2/3O3)- 0.35PbTiO3 (x=0, 0.02, 0.05) ferroelectric ceramics. Dielectric and AC impedance spectroscopic measurements were carried out on pure and lanthanum doped PMN/PT ceramics over a wide temperature (30o- 450o C) and frequency interval (10 Hz-1 MHz). Pure and lanthanum doped Pb1-xLax[(Mg1+x/3Nb2-x/3)0.65Ti0.35(1-x/4)]O3, (x=0, 0.02, 0.05) ceramics were prepared by solid state reaction route using columbite precursor method. X-ray diffraction revealed tetragonal (P4mm) phase for pure PMN/PT ceramics and transition to pseudo cubic phase (Pm3m) was observed with increased lanthanum doping. The dielectric response of the lanthanum modified PMN/PT ceramics was interpreted in terms of modified curie weiss law. Modulus spectroscopy revealed the deviation of dielectric behavior from ideal Debye behaviour. Activation energies calculated from dielectric relaxation and modulus spectroscopy suggested that charge transport processes are due to oxygen ion hopping.The AC conductivity of the PMN/PT ceramics initially increased for 2 mol% of lanthanum doping followed by a subsequent decrease with further 5 mol% of lanthanum doping. The value of the activation energies calculated from the temperature dependance of ac conductivity was in the range from 1.20-1.48 ev which is due to doubly ionized oxygen vacancies. The overall structural, electrical and dielectric behaviour of Pb1-xLax[(Mg1+x/3Nb2-x/3)0.65Ti0.35(1-x/4)]O3, (x=0, 0.02, 0.05) ceramics is correlated to the relaxor nature induced by lanthanum doping.
Sathosh K. Kurni; Pradip Paik
Abstract
SiO2 nanoparticles of average size 15-20 nm have been synthesized and its dielectric properties have been investigated as a function of frequency (between 20 Hz to 2 MHz). A very high dielectric constant of ca. 14000 at 20 Hz and at room temperature has been observed which is very high compared to the ...
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SiO2 nanoparticles of average size 15-20 nm have been synthesized and its dielectric properties have been investigated as a function of frequency (between 20 Hz to 2 MHz). A very high dielectric constant of ca. 14000 at 20 Hz and at room temperature has been observed which is very high compared to the conventional bulk SiO2 particles (ca. 50-100). For this new SiO2 the loss value is found to be less than 1. These SiO2 nanoparticles with high dielectric constant and low loss can be offered its use in constructing high efficient electronic circuit boards and storage devices. Spectra between real and imaginary parts of dielectric constant reveal an inclined line with depressed semicircle. Impedance measurements have been performed to know the electrical properties of the novel SiO2 nanoparticles. XRD, TEM and FTIR characterizations confirm the solid state network structural, morphological shape and size, and chemical functionality of SiO2 respectively. Copyright © 2016 VBRI Press
