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We report the structure, microstructure, dielectric, and transport properties of the dysprosium (Dy) modified lanthanum bismuth oxide (LaBi0.85Dy0.15O3) synthesized by the solid-state reaction method. The Rietveld refinement of the X-ray diffraction (XRD) data was done using MAUD software which adopts an orthorhombic crystal system. Scherer's formula was used to calculate crystallite size, which is found to be 25.2 nm. An analysis of a scanning electron microscope (SEM) image indicates that the grains have an even distribution throughout the whole sample surface with well-defined grain boundaries. Once more, compacted grains and clearly defined grain boundaries may have an impact on the conduction mechanism in the sample. The energy dispersive analysis of the X-ray (EDX) spectrum provides that all the constituent elements are present in the both weight and atomic percentage in the sample. The generated sample appears to reflect the Maxwell–Wagner type of dielectric dispersion, in accordance with research on the dielectric characteristics as a function of temperature and frequency. While impedance evaluation confirms the existence of the negative temperature coefficient of resistance (NTCR), the modulus plot analysis indicates a non-Debye kind of relaxation mechanism. A thermally activated conduction mechanism is present, according to the study of the ac conductivity plot. Again, the study of the Nyquist and Cole–Cole plots shows that semiconducting behavior is consistent with several applications involving energy storage devices. [ABSTRACT FROM AUTHOR]

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 85.6 nm 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 1.8 eV, 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. [ABSTRACT FROM AUTHOR]

In this paper, synthesis (solid-state reaction) and characterization (XRD, SEM, EDX, RAMAN, UV & LCR) of a double perovskite: BiLaCoMnO6 (BLCMO) are reported. The structural analysis suggests monoclinic crystal symmetry with average crystallite size = 79.6 nm and lattice strain = 0.00149 respectively. The analysis of the scanning electron microscopy (SEM) micrograph suggests the uniform distribution of grains. The analysis of energy-dispersive X-ray spectroscopy (EDX) spectrum suggests the presence of all constituent elements (Bi, La, Co, Mn & O) in both weight and atomic percentage. The study of the Raman spectrum provides information about the atomic vibration of all the constituent elements. The study of the UV visible spectrum provides of bandgap energy of 2.06 eV and impedance spectroscopy suggests a negative temperature coefficient of resistance (NTCR) character, while the modulus study predicts the presence of a non-Debye type of relaxation. The study of temperature-dependent resistance supports NTC thermistor applications. [ABSTRACT FROM AUTHOR]

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 40.7 nm 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 2.1 eV, 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 ∼ T) supports NTC thermistor character for temperature sensor applications. The analysis of the P-E loop reveals the possibility of the ferroelectrics' character. [ABSTRACT FROM AUTHOR]

Cerium doped strontium manganese (SrMn0.97Ce0.03O3) ceramics was prepared by solid state reaction route. The structural analysis suggests a hexagonal structure (P63/mmc) with refine lattice constants are; a = b = 0.5532 nm , c = 0.9108 nm , α = β = 90 ° , γ = 120 ° , ρ = 5.42 g/cm3, and V = 241.38 × 10 6 pm 3. The average crystallite size and micro-strain in the material are 35.8 nm and 0.0717%, respectively. The study of SEM micrograph suggests a highly dense material with small porosity. It is clearly noticed that material has well defined grains surrounded by grain boundaries with average grain size is 9.5 μm, which play important role to define electrical properties. Activation energy increases from 275 meV to 504 meV with temperature in the material confirms a thermally activated conduction process, which is also well supported from decreasing tendency of diameter of Nyquist plots. Temperature dependent relaxation time graph suggests two conduction channels (Ea1=212 meV & Ea2 = 51 meV) i.e. immobile charge carriers at low-temperature while defects at higher temperature. The gap between the peak of Z '' and M '' is becoming wider with temperature confirming non-Debye-type relaxation character. The bulk resistance (Rb) decreases from 8.622 × 103 Ω at 25 ° C to 1.380 × 102 Ω at 500 ° C after fitting (CQR) (CR) model with Nyquist plot supporting the NTCR behavior of the material, which is well supported from Cole-Cole plots. Prepared material can be used in cathode for making solid oxide fuel cells (SOFCs) and biosensors. [ABSTRACT FROM AUTHOR]

In this communication, the cerium (Ce) modified (Bi0.4Fe0.4)(Pb0.6Ti0.3Ce0.3)O3 (BF-PT) ceramics is prepared by conventional solid-state reaction technique. The compound is found to crystallize in the rhombohedral crystal system with space group R-3c (#167). The refined lattice parameters are a = b = 4.989 Å, c = 17.062 Å, α = β = 90 ∘ , γ = 120 ∘ , V = 367.78 Å3 and ρ = 2.71 g/cm3 (JCPDS No.-00-005-0586). The average crystallite size and lattice micro-strain in the ceramics are estimated at 47.6 nm and 0.117% respectively. Scanning electron microscopy analysis indicates low porosity and well-defined grain boundaries, with an average grain size of 13.7 μm. Raman spectroscopy confirms the presence of all constituent elements and ferroelectric character. Ultraviolet–visible (UV–Vis) spectroscopy analysis suggests a bandgap of 1.72 eV for the modified BF-BT ceramics, which is suitable for photovoltaic applications. The study of complex impedance suggests a Cole–Cole-type relaxation with a decrease in bulk resistance from 6.283 × 1013 Ω cm2 at 25°C to 1.783 × 104 Ω cm2 at 500°C, confirming the negative temperature coefficient of resistance. The calculated activation energies are 849.8 meV, 706.5 meV, 575.1 meV, and 499.4 meV at 1 kHz, 10 kHz, 100 kHz, and 1000 kHz, indicating ionization of oxygen vacancy and the involvement of the released electrons in the hopping conduction process, and support a thermally activated conduction mechanism. The increase in the peak frequency difference between the Z ″ and M ″ spectrum with temperature suggesting a non-Debye-type relaxation in the material. The material is characterized to a high dielectric constant and low tangent loss suitable for optoelectronic devices. [ABSTRACT FROM AUTHOR]