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The ferroelectric solid solutions described by a general formula 0.98Pb(Zr1-xTix)O3 – 0.02La(Fe3+0.5, Nb5+0.5)O3 have been obtained by solid state reaction technique, where x assumes the following values: 0.42, 0.48 and 0.58. The structure of these ferroelectric compositions has been investigated in detail using X-ray diffraction analysis (XRD) and Scanning Electron Microscopy (SEM). The results obtained by XRD have evidenced that all obtained samples have a perovskite structure. The influence of the sintering temperature on the degree of incorporation of the elements in the solid solution have been studied too. The dielectric and piezoelectric constants have been determined and the influence of temperature on obtained values are presented and discussed. The performed experimental results have pointed out that the materials are characterized by a high anisotropy. Furthermore, the obtained values of the electromechanical coupling factor (kp) is situated between 0.40÷0.65 depending on the composition and the sintering temperature too.

The influence of the sintering temperature on the structure and on the hysteresis loops of Fe3+ doped Pb(ZrxTi1-x)O3 system has been investigated. Three compositions have been selected in the following mode: one in rhombohedral region, one in MPB region and one in tetragonal region have been obtained by solid state reaction technique. Sintering has been carried out at 12000C and 12500C respectively. The nature of the phases has been investigated in detail using X-ray diffraction analysis (XRD). All the sintered samples reveal a perovskite type structure. The surfaces have been lapped and metalized in order to obtaine the hysteresis loops at room temperature. The results showed a similar behaviour with “hard” PZT ceramics.

In the present paper (1-x)Pb (Zr1-yTiy)O3 – xPb (Mn1/3Sb2/3)O3 – z at%E system, with E = Pr3+, Nd5+ and Gd3+ where x = 0.12; y = 0.48; z = 0 and 0.02 ceramic synthesized by solid state reaction technique is analysed. The investigation aims studying of the effect of dopants on the dielectric and piezoelectric properties of such piezoelectric ceramic. The prepared powders have been uniaxially pressed into discs with diameter of 10 – 12 mm and thickness of 1.2 mm. Sintering has been carried out in air atmosphere at temperatures of 1150°C and 1200°C, respectively, for 2 hours each, followed by a controlled cooling at a rate of 200°C /h. The piezoelectric properties have been investigated after a suitable preparation, including polishing, metallization. The structure of the samples has been determined by X-ray diffractometry (XRD), while the morphology and grains size have been investigated by the scanning electron microscopy (SEM). The piezoelectric properties have been studied by the resonance - antiresonance method. XRD analysis reveals a perovskite tetragonal structure and, as expected for ceramic materials, SEM analysis indicates that the average grain size increases as sintering temperature increases. The dielectric and piezoelectric properties have been determined measuring the ceramic discs, and properties, as dielectric permittivity (εr), dielectric loss (tg δ), and the electromechanical coupling factor (kp) have been obtained. The acquired results indicate a significant effect of the dopants on the dielectric and piezoelectric properties of such materials.

0.88Pb(Zr0.52Ti0.48)O3 – 0.12Pb(Mn1/3Sb2/3)O3 – 0,02 at%E piezoelectric ceramics, with E = Pr3+ were synthesized by using a conventional method, namely a solid state reaction technique. X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM) were employed for the structural and microstructural investigations. Piezoelectric methods were used for the dielectric and piezoelectric properties determination. The results of XRD show a perovskite structure and XRD patterns, indexing on a tetragonal cell structure, was carried out for the most common phases. The SEM micrographs of the sintered compositions reveal a homogenous structure with a sharp or rounded grain boundary. The modified PZT ceramic presents still superior piezoelectric properties. Based on the results obtained, one can conclude that the analysed piezoelectric ceramics are useful for device applications.

The concept of more electrical aircraft architecture requires new magnetic materials, with improved magnetic and electrical properties. The paper investigates the soft magnetic materials based on FeCo/Al2O3 core-shell nanoparticles, synthesized by sol-gel technique. These nanomaterials combines the high saturation magnetisation of FeCo compound with the increased resistivity of Al2O3 and allow the decreasing of time-dependent magnetic losses for the bulk sized components, compared with the currently available Fe-Si alloys, used as metallic punched sheets for the building of the magnetic cores in electrical machines. The main physical characteristics of the FeCo/Al2O3 prepared nanomaterials are: saturation magnetisation in the range of 136–213 emu/g, coercivity around 24.5 kA/m (320 Oe) and electrical resistivities of order of 1014 Ω·m.