Effect of Vanadium Doping on Microstructure and Dielectric Behavior of CaCu<sub>3</sub>Ti<sub>4</sub>O<sub>12</sub> Ceramics

Abstract

Abstract:In this work, effect of vanadium doping of CaCu 3 Ti 4 O 12 (CCTO) on microstructure and complex dielectric constant over wide frequency (100 Hz-1 MHz) and temperature (0°C -160°C) ranges has been studied. The vanadium doping of CCTO system results in an increase of grain size, the grains being surrounded by melted-like grain boundaries. Real parts of dielectric constant of all samples are similar at low frequency (<1 kHz). In doped samples, above 1 kHz, a relaxation appears which is evidenced by a drop of real part of permittivity and a peak of its imaginary part. This relaxation phenomenon is very significant at relatively low doping rates and then decreases again as vanadium content increases. AC conductivity behavior of vanadium-doped CCTO can be divided in three regions depending on conduction processes. The calculated activation energies were close to 0.46 eV.

Dielectrics Properties and Temperature Dependence of Electron Spin Resonance of Doped Molybdenum CCTO

“…It explains that Mo is preferentially returned in the CCTO structure. At this temperature, CCTO doped with molybdenum has the same effect on the grain growth like GeO 2 and V 2 O 3 content obtained in previous studies [11,13]. (Figure 3).…”

“…Authors also report the influence of different doping CCTO solid phase. Thus, while the addition of compounds such as TeO 2 , Cerium, Cesium, and Eu 2 O 3 greatly reduce permittivity material [7][8][9], oxides such as P 2 O 5 , GeO 2 , Lu 2 O 3 and V 2 O 3 increase the dielectric constant [10][11][12][13]. When doping is carried out by partial substitution of Ca or Ti sites, we have generally a reduction of the permittivity of the material by substitution on the sites of the first one (Gd et Pr) [14,15] and an increase on the sites of the second one (Nb, Fe, Co, Ni) [16][17].…”