The aim of this research was to fabricate and study the properties of Bi1-x DyxFeO3 (for x = 0, 0.05, 0.07, 0.1) ceramics materials. Simple oxide powders Bi2O3, Dy2O3 and Fe2O3 were used to fabricate Bi1-xDyxFeO3 ceramics by mixed oxide method followed by free sintering. The study presents changes in microstructure and crystal structure as well as in dielectric properties and magnetic properties caused by modification of BiFeO3 with dysprosium dopant.

An optimized method of vibration Energy Harvesting is based on a step-down transformer that regulates the power flow from the piezoelectric element to the desired electronic load. Taking into account parameters of the whole system, the “optimal” voltage gain the piezoelectric transformer can be determined where the harvested power is maximized for the actual level of mechanical excitation. Consequently the piezoelectric transformers can be used to boost up the conversion of mechanical strain into electrical power with considerable potential in Energy Harvesting applications. Nowadays however, the most important factor is usage of lead free material for its construction. Additional desired parameters of such ceramics include high value of piezoelectric coefficients, low dielectric losses and reasonable power density. This work for first time proposes a lead free K0.5Na0.5NbO3 (KNN) material implementation for stack type of piezoelectric transformer that is designed for load efficiency optimization of vibration energy harvester.

Multiferroic six-layer Aurivillius type Bi7Fe3Ti3O21 ceramics was obtained by conventional mixed oxides method. The final sintering process was taken in several different sintering times, which determined changes in properties of discussed ceramic material. The structure and dielectric properties of the material are reported. In order to examine the technological conditions on the crystal structure, XRD analysis was carried out. The microstructure, as well as the quantitative and qualitative analysis of the chemical composition were investigated by scanning electron microscope with an energy dispersion spectrometer. The main purpose of the paper is to present the effect of sintering time on the microstructure, crystallographic structure and dielectric properties of Bi7Fe3Ti3O21 ceramics.

La0,7Ca0,3MnO3 polycrystalline were synthesized from La2O3, CaO and MnO2 powder mixture using a solid state reaction technique. The compound powders were obtained through the free sintering method at different temperatures and sintering times in order to study the influence of technological conditions on Ca doped La manganites. The most important physical features as structure, microstructure and morphology were described after X-ray diffraction investigation. Photographs of the specimen fractures were taken with SEM (scanning electron microscope) and they revealed high porosity of the tested material and great tendency for its grains to create agglomerates. Influence of doping and technological conditions on lattice parameters were studied by means of Rietvield analysis. The XRD measurements reveal that La0,7Ca0,3MnO3 has orthorhombic symmetry with Pnma space group.