Synthesis and study of Structural, Microstructural and Dielectric Properties of Ce3+ doped Co-Ni Ferrites for automotive applications

Nano crystalline spinel ferrites of Co0.5Ni0.5CexFe2−xO4 (x=0.01, 0.015, 0.02, 0.025 and 0.03) was prepared by modified solution combustion method using a mixture of fuels for the first time. The influence of rare earth Ce3+ substitution at the Fe3+ site on the structural, microstructural and dielectric properties of Co0.5Ni0.5CexFe2-xO4 was investigated. The X-ray diffraction (XRD) studies confirmed the formation of monophasic nano crystalline samples without any secondary phases. The crystallite size decreases and density increases with the increases of Ce3+ contents. Surface morphology was studied through Scanning Electron Microscopy (SEM). Dielectric properties of these ferrites have been studied at room temperature using impedance analyzer in the frequency range up to 20 MHz. The effect of frequency and composition on dielectric constant (ε’), dielectric loss (tanδ) and ac conductivity (σac) have been discussed in terms of hopping of charge carriers (Fe2+↔Fe3+). The decrease in dielectric loss with frequency follows Debye's relaxation phenomena. Both the variation in tan loss and dielectric loss with frequency shows a similar. AC conductivity increases with the increases of frequency which directly proportional to concentration of Ce3+ ions follows Jonscher law. These Cerium doped Cobalt-nickel ferrites are very helpful for automotive applications

Raman spectroscopy of BaTiO3 based ceramics

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Effect of heavy metal oxides on photoluminescence and spectroscopic attributes of Eu3+ activated borate glasses

Influence of Heavy Metal Oxides (HMOs: PbO and Bi2O3) on structural and photoluminescence (PL) properties Eu3+ activated lanthanum borate glasses has been analyzed and discussed in thoroughly here. When the PbO is loaded more and more in the glass system, the luminesce intensity and lifetime values of D-5(0) -> F-7(2) transition of Eu3+ were improved for the excitation at 464 nm due to enhanced covalency of Eu-O bonds arose from the dual function of lead oxide in the structure of PbO varied glasses. The betterment in luminescence features are also attributed to the decrease of effective network phonon energy occurred because of the incorporation of lead oxide in the glass composition. On the other hand, the luminesce (emission intensity and lifetime values of 614 nm emission of Eu3+ under 464 nm excitation) results are completely upending as the Bi2O3 content increased gradually in the glass matrix. This reduction in luminescence properties are ascribed to the decrease of covalency of Eu-O and thus crystal field in the vicinity of Eu3+ site. The reduction of covalent character of Eu-O is due to two facts, one being the newly generated NBOs owing to the generation of BiO6 units with the incorporation of Bi2O3 in the glass matrix and the second, the development of Bi-O-Bi and Bi-O-B linkages. The luminescence and spectroscopic attributes evidently reveal the lead varied borate glass hosts are more beneficial than Bi2O3 varied borate glass hosts for optoelectronic applications