The purpose of the present study was to learn the morphological, structural, ferroelectric, dielectric, electromechanical, magnetoelectric, and magnetic properties, and DC conductivity of BaTiO₃-Ni_0.64Zn_0.36Fe₂O₄ (BT-F) multiferroic composites compacted via the free sintering method. The influence of the ferrite content in ceramic composite materials on the functional properties is investigated and discussed. X-ray diffraction studies confirmed the presence of two main phases of the composite, with strong reflections originating from BaTiO₃ and weak peaks originating from nickel-zinc ferrite. BT-F ceramic composites have been shown to exhibit multiferroism at room temperature. All studied compositions have high permittivity values and low dielectric loss, while the ferroelectric properties of the BT component are maintained at a high level. On the other hand, magnetic properties depend on the amount of the ferrite phase and are the strongest for the composition with 15 wt.% of F (magnetization at RT is 4.12 emu/g). The magnetoelectric coupling between BT and F phases confirmed by the lock-in technique is the largest for 15 wt.% ferrite. In the present work, the process conditions of the free sintering method for obtaining BT-F multiferroic composite with good electrical and magnetic properties (in one material) were optimized. An improved set of multifunctional properties allows the expansion of the possibilities of using multiferroic composites in microelectronics.

In the work, the multicomponent Pb_0.75Ba_0.25(Zr_0.65Ti_0.35)_1-aSn _a O₃ (PBZT/Sn) ceramics were obtained with various tin amounts (a from the range of 0.0 to 0.1). The densification of the PBZT/Sn ceramic samples was performed using pressureless sintering method. The effect of SnO₂ content on the crystal structure of PBZT/Sn ceramics, microstructure, DC electrical conductivity and electrophysical properties (including dielectric and ferroelectric testes), were investigated. The PBZT/Sn ceramic samples exhibit high values of dielectric permittivity at the temperature of ferro-paraelectric phase transition and show the relaxor character of phase transition. Excessive SnO₂ contents doping of the PBZT/Sn materials (already for a = 0.1) might lead to lattice stress and structure defects, which successively leads to the deterioration of ferroelectric and dielectric properties of the ceramic samples. The presented research shows that the addition of SnO₂ to the base PBZT compound (in the proper proportion) gives an additional possibility of influencing the parameters essential for practical applications, from the areas of micromechatronics and microelectronics.

The ceramic samples of solid solution (1-x)[0.5(PbZr_0.53Ti_0.47O₃)-0.5(PbFe_2/3W_1/3O₃)]-x(PbFe_1/2Nb_1/2O₃) [i.e. (1-x)(0.5PZT-0.5PFW)-xPFN] with x = 0; 0.1; 0.2 have been obtained by conventional ceramic technology using the free sintering (FS) method from PbO, ZrO₂, TiO₂, Fe₂O₃, WO₃ and Nb₂O₅ oxides. Basing on the literature data for individual components, it can be expected that this material ought to have interesting multiferroic properties. The presented work is the first step in obtaining and investigating this solid solution. In the presented paper, the technology and the results of investigations of EDS, XRD, the microstructure of fractured samples, dielectric permittivity v.s. temperature, and d.c. electric conductivity are presented.