Doped Sb₂Te₃ narrow-band-gap semiconductors have been attracting considerable attention for different electronic and thermoelectric applications. Trivalent samarium (Sm)- and indium (In)-doped Sb₂Te₃ microstructures have been synthesized by the economical solvothermal method. Powder X-ray diffraction (PXRD) was used to verify the synthesis of single-phase doped and undoped Sb₂Te₃ and doping of Sm and In within the crystal lattice of Sb₂Te₃. Further, the morphology, structure elucidation, and stability have been investigated systematically by scanning electron microscopy (SEM), Raman analysis, and thermogravimetric analysis (TGA). These analyses verified the successful synthesis of hexagonal undoped Sb₂Te₃ (AT) and (Sm, In)-doped Sb₂Te₃ (SAT, IAT) microstructures. Moreover, the comparison of dielectric parameters, including dielectric constant, dielectric loss, and tan loss of AT, SAT, and IAT, was done in detail. An increment in the electrical conductivities, both AC and DC, from 1.92 × 10^-4 to 4.9 × 10^-3 Ω^-1 m^-1 and a decrease in thermal conductivity (0.68-0.60 W m^-1 K^-1) were observed due to the doping by trivalent (Sm, In) dopants. According to our best knowledge, the synthesis and dielectric properties of (Sm, In)-doped and undoped Sb₂Te₃ in comparison with their electrical properties and thermal conductivity have not been reported earlier. This implies that appropriate doping with (Sm, In) in Sb₂Te₃ is promising to enhance the electronic and thermoelectric behavior.

To synthesize lithium ferrite with various Gd concentrations (Li _0.5 Fe _2.5−x Gd _x O ₄ ), x = 0.00, 0.025, 0.05, 0.075, 0.1, solutes were dissolved in glycol, i.e. by using the without water and surfactant (WOWS) sol–gel method. X-ray diffraction (XRD) analysis confirmed that the material possessed an inverse spinel cubic structure and is single phase. Pellets of all samples were sintered at 700 °C and XRD confirmed that samples were crystalline, phase pure and had an inverse spinel cubic lattice. Scanning electron microscopy indicated that the grains were agglomerated and had a predominantly spherical shape. It is concluded that Gd acts as a grain refiner in lithium ferrite up to a Gd concentration of 0.05. AC conductivity and dielectric constant increased by increasing Gd concentration. The Maxwell–Wagner model and Johnsher’s power law were used to explain the dielectric properties. DC conductivity was measured from 100 to 600 °C. DC conductivity was explained by the hopping mechanism. It is concluded that DC resistivity and dielectric constant values are related reciprocally in the prepared sample. AC electrical properties were also measured at a constant frequency of 1 MHz in the temperature range from 400 to 600 °C. Gd-substituted lithium ferrite showed high AC conductivity, high DC resistivity and constant dielectric values, but low dielectric loss values as compared to pure lithium ferrite.