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This paper outlines the investigation of structural, dielectric, complex impedance and optical properties of lanthanum-modified (Bi${}_{0.5}$La${}_{0.5}$Fe)${}_{0.5}$(Bi${}_{0.5}$Na${}_{0.5}$Ti)${}_{0.5}$O₃ (BLF–BNT) single perovskite oxide synthesized by conventional solid-state reaction method. From Rietveld refinement, the crystal structure of the BLF–BNT ceramic has confirmed a tetragonal and the estimated average crystallite size is found to be 43.6nm. The dielectric properties of the La-doped BLF–BNT ceramic reveal the presence of Maxwell–Wagner-type dielectric dispersion. This suggests the occurrence of charge accumulation at grain boundaries and interfaces within the material. The complex impedance and complex electric modulus studies were employed to gain insight into the microscopic dielectric relaxations and conduction processes of the material. The electric modulus spectroscopy reveals the existence of nonDebye-type relaxation processes, including localized and long-range relaxation processes. The Nyquist and Cole–Cole plots show the semiconducting nature of the BLF–BNT ceramic. With the help of the Arrhenius method based on the imaginary portion of the electrical impedance and modulus, activation energies and relaxation times have been estimated. These parameters contribute to a deeper understanding of the electrical properties and conduction mechanisms within the material. Further, Raman spectroscopy, a nondestructive chemical analysis technique, was conducted to confirm the composition and structural integrity of the proposed system through its atomic vibrations. Also, the bandgap energy of the material has been estimated using Tauc’s relation and is found to be 1.69eV.

This signifies that the BLF–BNT ceramic possesses a suitable bandgap for certain device applications, making it a promising candidate in various technological fields. Moreover, the overall comprehensive study of the proposed ceramic provides valuable insight and opens new possibilities for its potential applications in various electronic devices.

Impedance spectroscopy (IS) is a non-destructive technique used for obtaining valuable information about bulk conductivities, dielectric constants, phase composition and grain boundaries of important ceramic materials, amongst many others. We obtained Nyquist plots for four different hot-pressed Si₃N₄ samples in two different frequency regimes: 1 Hz to 30 MHz and 1 kHz to 100 kHz. The information obtained was compared against results from scanning electron microscopy (SEM) and X-ray diffraction (XRD). The limitations of the frequency response techniques are also discussed.

A novel lead zinc titanate tungsten oxide (PbZn${}_{1∕3}$Ti${}_{1∕3}$W${}_{1∕3}$O${}_3)$ single perovskite was synthesized employing a cost-effective solid-state reaction technique. A phase transition occurs from tetragonal (P4mm) to monoclinic (C2/m) after substituting zinc (Zn) and tungsten (W) into the B-site of the pure lead titanate. The average crystallite size and micro-lattice strain are 66.2nm and 0.159%, respectively, calculated by the Williamson–Hall method. The grains are uniformly distributed through well-defined grain boundaries and the average grain size is about 17.8$\mu$m analyzed from the SEM micrograph. Raman spectrum suggests the presence of all constituent elements in the sample. The UV–Visible study suggests that the sample is suitable for photovoltaic applications because of high bandgap energy $E_g=4.17$eV. The dielectric study confirms the negative temperature coefficient resistance (NTCR) behavior of the sample. The activation energy increases from 13.9meV to 142meV with a rise of temperature suggesting that ac conductivity is thermally activated. The thermally activated relaxation process was managed by immobile charge carriers at low temperatures while defects and oxygen vacancies at higher temperatures. The presence of the asymmetrical curves in modulus plots confirms the non-Debye-type behavior. Both Nyquist and Cole–Cole semi-circular arcs confirm the semiconductor nature of the sample.

The rare earth element ytterbium based lead-free perovskite BiYbO₃ was successfully synthesized by cost effective solid-state reaction technique. The analysis of the XRD reflection peaks revealed that BiYbO₃ crystallizes with cubic $Fm3m$ single phase crystal system having cell parameter $a=5.377$Å. The decrease in the dielectric permittivity with frequency was found to follow the accepted Maxwell–Wagner model of interfacial polarization. The reported perovskite was found to be stable up to $450^{°}$C as evident from the low $\text{tan}\delta$ values. The bulk capacitance of BiYbO₃ decreases from 1.619nF/cm² to 0.173nF/cm² with the rise in temperature from $25^{°}$C to $450^{°}$C. The dielectric data shows that BiYbO₃ perovskite follows a negative temperature coefficient of resistance (NTCR) trend. The information obtained from the Nyquist plot and the Cole–Cole electric modulus plot is complementary to each other. The effect of bulk and grain boundary is clearly visible in the Cole–Cole electric modulus plot, whereas a good fit of the equivalent circuit $\{(CQR)(CR)\}$ in the Nyquist plot gave important bulk and grain boundary (capacitance and resistance) parameters. The AC-conductive study for this rare earth perovskite is used to obtain the activation energies to understand the semiconducting behavior of BiYbO₃.

In this paper, the synthesis and characterization (structural, dielectric, electrical and optical) of a double perovskite, BaSrZrMnO₆ (BSZMO), by a conventional solid-state reaction route are reported. The sample has an orthorhombic crystal symmetry with an average crystallite size of 40.7nm and a micro-lattice strain of 0.226%. A microstructural and compositional analysis was presented by using a scanning electron microscope (SEM) and energy dispersive x-ray analysis (EDX), respectively. Grains are well-grown and distributed uniformly through well-defined grain boundaries on the sample surface to enhance physical properties. EDX analysis confirms the presence of all constituent elements and is well-supported by the Raman study. The analysis of the UV–Visible spectrum reveals an energy bandgap of 2.1eV, suitable for photovoltaic applications. The study of dielectric properties as a function of temperature and frequency reveals a Maxwell–Wagner type of dispersion and explores possible applications in energy storage devices. The discussion on the impedance spectroscopy supports the negative temperature coefficient of resistance (NTCR) character whereas the modulus study suggests a non-Debye type of relaxation in the sample. The study of AC conductivity confirms a thermally activated relaxation process. Both Nyquist and Cole–Cole plots support the semiconducting nature of the sample. The study of resistance versus temperature ($R\sim T$) supports NTC thermistor character for temperature sensor applications. The analysis of the P-E loop reveals the possibility of the ferroelectrics’ character.

In the present investigation, the synthesis of the strontium copper titanate $({\mathrm{\text{Sr}}}_3{\mathrm{\text{CuTi}}}_4{\mathrm{\text{O}}}_{12},\mathrm{\text{SCTO}})$ ceramic by the cost-effective solid-state reaction was reported. The structural analysis suggests a single-phase tetragonal crystal symmetry with space group P4/mmm. The average crystallite size and mechanical compressive microlattice strain are found to be 65.8nm and 0.000594, respectively. The study of the field emission scanning electron microscope (FESEM) micrograph suggests that grains and grain boundaries are uniformly distributed on the sample surface with less porosity. The study of Raman lines suggests the presence of all constituent elements, which is well supported by EDAX analysis. The UV–Vis spectroscopy analysis shows that the bandgap of SCTO is about 3.2eV suitable for photovoltaic and other higher-temperature sensor applications. The decrease of dielectric constant with frequency supports the reduction of space charge polarization. The modulus analysis suggests that the immobile charge carriers at lower and defects and oxygen vacancies at higher temperatures are responsible for the thermally activated conduction process. The calculated activation energies are 4.54meV, 4.40meV, 3.39meV and 3.29meV at 1kHz, 10kHz, 100kHz and 1MHz; the decrease with the rise of the frequency confirms a thermally activated conduction process. Thermistor constant $(\beta )$, sensitivity factor $(\alpha )$ and stability factor of the sample were calculated, which confirms the characteristics of the NTC thermistor. The Nyquist and Cole–Cole semicircular arcs confirm NTCR character and are found to be suitable applications for energy storage devices and thermistors.

In this communication, the synthesis (solid-state sintering) and characterization of a double perovskite BiFeMoO₆ are reported. Analysis of X-ray diffraction (XRD) data provides monoclinic crystal symmetry with an average crystallite size of 85.6nm and lattice strain of 0.00078, respectively. The microstructural analysis of the sample was done using a scanning electron microscope (SEM) and the results show that grains are well-grown and distributed uniformly throughout the sample surface. The grains are visible clearly due to well-defined grain boundaries, and the effect on the mechanism of electrical ac conductivity was studied. The compositional purity of the sample was checked by energy dispersive X-ray (EDX) analysis spectrum which supports the presence of all constituent elements (Bi, Fe, Mo and O) in both weight and atomic percentages. The study of the Ultraviolet–Visible spectrum provides a bandgap energy of 1.8eV, suitable for photovoltaic applications. The measurements of the dielectric were used to confirm the existence of the Maxwell–Wagner type of dispersion. The study of impedance spectroscopy helps to understand the negative temperature coefficient of resistance (NTCR) character while the electrical modulus measurements claimed a non-Debye relaxation mechanism in the sample. The study of ac conductivity reveals the fact of thermally activated conduction mechanism in the sample. The presence of the semiconducting nature of the sample was checked from both Nyquist plots and Cole–Cole plots. The study of the resistance versus temperature reveals the fact of negative temperature coefficient (NTC) thermistor character and is suitable for some temperature sensor devices.