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In this paper, detailed studies of effect of small amount of manganese substitution (at the zirconium site) on the structural, micro-structural, and electrical characteristics of lead zirconate titanate of Pb(Zr0.35–xMnxTi0.65)O3;x = 0, 0.02, 0.06, 0.10 (PZMT)) have been reported. The materials were prepared by using standard ceramic technology. The formation of the compounds and their basic crystal data have been studied through X-ray diffraction (XRD) method. The crystallite size and lattice strain of the compounds, evaluated from Scherrer's and Hall Williamson (H-W) equations, is found to be in the range of 40–50 nm and 11 × 10−4 to 50 × 10−4, respectively. Microstructures of different magnifications, revealing the surface nature of the compounds, have been recorded by field emission scanning electron microscope (FESEM). Effect of Mn+4 ions on electrical behavior (electrical impedance (Z*), electrical modulus (M*), conduction and relaxation phenomenon) of PZMT systems, over wide range of temperature and frequency, has been studied. [ABSTRACT FROM AUTHOR]

In this article, the synthesis (through a mixed oxide route, calcination temperature = 850 °C, sintering temperature = 870 °C, for time= 6 h) and characterization (structure, dielectric, and electrical properties) of Gd modified bismuth titanate Bi4Ti3O12 of a chemical composition Bi3.8Gd0.2Ti3O12 of Aurivillius family in ceramic form have been reported. The development of an orthorhombic structure (with a minor secondary phase) with a space group B2ab has been confirmed by analyzing room temperature X-rays diffraction pattern/data. Studies of some electrical parameters like loss tangent, dielectric constant, electric impedance, and conductivity have provided valuable data and information on conduction mechanism, structure-properties relationship, etc., in the 25–500° C temperature range at different frequencies (1 kHz − 1MHz). The presence of grain, grain boundary is confirmed from the Nyquist plot. The Nyquist plot also confirms the existence of non-Debye relaxation in the material. The frequency and temperature significantly impact the material's various properties (dielectric and electrical). [ABSTRACT FROM AUTHOR]

In this paper an experimental study of different piezoelectric materials for energy harvesting applications, as well as experimental results for various types of piezoelectric materials and piezoelements were presented. Various types of hot-pressed and conventionally sintered PZT piezoceramics, porous PZT piezoceramics, and multilayer PZT/PZT ceramic piezocomposites with diverse ferroelectric “hardness” were fabricated, optimized and tested. Experimental results comprising cyclic loading at different load resistances and mechanical stresses for different types of piezoelements were presented. It was shown that porous ceramics (relative porosity 20%, d33= 410 pC/N, ϵT33/ϵ0= 1100) provide 1.5–2 times higher power efficiency at cyclic loadings than the dense hot-pressed ceramics and can be used as piezogenerators at low loading pressures (up to 5 MPa). The possible applications of developed materials in energy harvesting devices as well as the empirical criteria of piezoelectric materials efficiency were discussed. [ABSTRACT FROM PUBLISHER]

Complex impedance and electric modulus spectroscopies were used to investigate the dielectric relaxation and conductivity of random oriented BiFeO3 thin films. Thermally activated charge transport models yielded activation energies of eV, which is consistent with an electrical conduction dominated by oxygen vacancies. The non-Debye behavior of impedance and electric modulus relaxations were modeled by Cole-Cole functions. Results suggest a coexistence of components from both long-range and localized relaxation in the studied BiFeO3 films dominated by grain boundaries. The dielectric relaxation induced by electric field does not follow the Arrhenius formalism. [ABSTRACT FROM AUTHOR]

NBT based ceramic composites (1-x) Na0.5Bi0.5TiO3-xSrTiO3where x = 0.05, 0.10, 0.15 and 0.2 are prepared by solid state sintering route. Individual phases are obtained through sol-gel method. Polarization characterization was done using P-E loop measurements at various temperatures for all samples. Psand d33values obtained are used to estimate electrostrictive coefficient (Q). Curves drawn between strain versus electric field showed butterfly like nature. The electrical characteristics of these composites are investigated using impedance spectra in the temperature range from room temperature (∼30°C) to 500°C at different frequencies in the range of 100Hz-1MHz. The effect of grain and grain boundary interface on the electrical properties of these composites with temperature and composition are evaluated from impedance data analysis. These samples showed a combined relaxation process due to individual phases, resulting in frequency spread. Bulk resistance (Rb) and bulk capacitance (Cb) values are estimated from semicircle fittings. The activation energies for conduction and relaxation for pure and composites helped to assess the conduction mechanism within the samples. The Vogel Fulcher fit helped in estimation of relaxations observed in the samples. [ABSTRACT FROM AUTHOR]

A new equation is proposed to describe the simultaneous temperature and frequency dependence of dielectric constant and impedance of relaxor ferroelectric compounds. It is applied to Ba(NdxTi1-2xNbx)O3relaxor compounds by non linear curve fitting to experimental data to check its validity in terms of fitted parameters obtained which have logical values. The validity can also be known from the regression value. This new equation may be used to characterize the dielectric behaviour of other relaxor ferroelectric compounds. [ABSTRACT FROM AUTHOR]