A wide range of the interesting properties of electroceramics Ba_0.996La_0.004Ti_0.999O₃ (BLT4) undoubtedly deserves differentiation and optimization. For this purpose, the corresponding donor oxide dope Fe₂O₃ was introduced in excess quantities into the base ceramics. In this way, an innovative ceramic material with the general formula of Ba_0.996La_0.004Ti_1−yFe_yO₃ (BLTF), for y = 0.001, 0.002, 0.003, 0.004, has been produced. The crystal structure of BLTF ceramics was investigated using X-ray diffraction. The diffraction peaks in XRD confirm the formation of the tetragonal perovskite phase. The electrical properties of BLTF ceramics have been tested using impedance spectroscopy, in the frequency range of 20 Hz–2 MHz and the temperature range of 20–580 °C. To gain absolute certainty on the consistency of the measured data, the obtained impedance spectra were analyzed using the Kramers–Kronig method. The usage of an equivalent circuit, proposed by the authors, allowed grain and grain boundary resistivity to be obtained. Based on the diagram of the natural logarithm of the mentioned resistivity versus the reciprocal absolute temperature, the activation energies of the conductivity processes have been determined. The values of activation energies indicated that the admixture of iron introduced into the BLT4 ceramics played a crucial role in the conductivity of grains and intergranular borders.

In this study, we investigate the dielectric, electric, and pyroelectric properties of Ba_1−xCa_xTiO₃ (BCT) ceramics with compositions of x = 0.2, 0.25, and 0.3. The ceramics were synthesized using the solid-state reaction method. A microstructural analysis was performed using scanning electron microscopy (SEM), revealing that calcium concentration influences grain size and morphology, with BCT20 showing larger, hexagonal grains, while BCT25 and BCT30 exhibited smaller, irregular grains. Phase composition and crystalline structure were characterized via X-ray diffraction (XRD), which confirmed the absence of secondary phases and a predominantly tetragonal P4mm structure for BCT20 and BCT25. However, BCT30 showed an additional orthorhombic (Pbam) phase at 5.9 wt. % alongside the dominant tetragonal phase. Dielectric measurements revealed that increasing the calcium concentration shifts the temperature of dielectric permittivity maximum to lower values, correlating with a shift in the ferroelectric–paraelectric phase transition. Pyroelectric measurements indicated the highest pyroelectric current for BCT25, while BCT30 showed the maximum thermally stimulated depolarization current.

Aurivillius BaBi₂Nb₂O₉ and Ba_1-xPr_xBi₂Nb₂O₉ ceramics were successfully synthesized by a simple solid state reaction method. Ceramics were prepared from reactants: Nb₂O₅, Bi₂O₃, BaCO₃ and Pr₂O₃. The microstructure, structure, chemical composition, and dielectric properties of the obtained materials were examined. Dielectric properties were investigated in a wide range of temperatures (T = 20–500 °C) and frequencies (f = 0.1 kHz–1 MHz). The obtained ceramic materials belong to the group of layered perovskites, crystallizing in a tetragonal structure with the space group I4/mmm. Modification of the barium niobate compound with praseodymium ions influenced its dielectric properties and introducing a small concentration of the dopant ion causes a slight increase in the value of electric permittivity and shifts its maximum towards higher temperatures.

The Pr³⁺-doped solid solutions from (Ba,Ca)(Ti,Zr)O₃ (BCTZO) system were successfully synthesized using an efficient and low-energy consuming route—the Pechini method combined with the sintering at relatively low temperature (1450 °C). The obtained materials were characterized by means of X-ray diffraction (XRD) and scanning electron microscopy (SEM). The dielectric properties were systematically studied. The Pr³⁺-doped BCTZO diphasic material generates intense and broad red photoluminescence (PL) emission at room temperature. The optical properties were significantly improved with the Ti⁴⁺ substitution by Zr⁴⁺ ions. As a result, the Pr³⁺-doped (Ba,Ca)(Ti,Zr)O₃ ceramics is a promising candidate for environmentally friendly, multifunctional material by combining good dielectric and photoluminescent properties with prognosis for the manifestation of strong photoluminescent and mechanoluminescent effects.

Pure Bi₇Fe₃Ti₃O₂₁ ceramic material and gadolinium ion (Gd³⁺)-doped ones were prepared by solid-state reaction method using simple oxides. The findings of the XRD measurements confirmed the initial author’s assumption that the dopant ions substituted in perovskite blocks influenced the dimensions of the unit cell parameters. All obtained materials are single-phase and show an orthorhombic structure with the Fm2m space group. Microstructure studies show that the admixture gadolinium doping changes the microstructure of the base material, changing grain shapes from plate-like to rounded. The temperature dependences of the electric permittivity have shown the existence of a maximum, the temperature location of which depends on both the frequency and the concentration of Gd³⁺ ions. The highest values of electric permittivity were characteristic of the material with an admixture of Gd³⁺ ions in the amount of x = 0.6 (f = 1 kHz), and the lowest values were for material with x = 0.2 (f = 1 kHz). Studies of the magnetoelectric effect have shown that the strongest coupling between magnetic and electrical properties was demonstrated by a material doped with Gd³⁺ ions in the amount of x = 0.2, for which the magnetoelectric coupling coefficient is equal to α = 12.58·10⁻⁹ s/m.

Ba_0.75Ca_0.25TiO₃ ceramics were successfully synthesized by a simple solid-state reaction method. This study examined the influence of sintering temperature on the structure, microstructure, dielectric properties and electrical behavior of the material. The XRD analysis reveals that the tetragonal phase (P4mm) is dominant in all the synthesized materials, with those sintered at T = 1400 °C and T = 1450 °C being single-phase, while others exhibit a minor orthorhombic phase (Pbnm). Higher sintering temperatures promoted better grain boundary formation and larger grain sizes. The electric permittivity increased with temperature up to T = 1400 °C, followed by a sharp decline at T = 1450 °C. Additionally, the Curie temperature decreased with increasing sintering temperature, indicating changes in phase transition characteristics. Thermal analysis showed that higher sintering temperatures led to sharper heat capacity peaks, while pyroelectric and thermally stimulated depolarization currents were maximized at T = 1400 °C due to oxygen vacancies. These findings highlight the significant impact of sintering temperature on the material’s structural and functional properties.