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The synthesis of lithium calcium germanate ceramic powders was achieved through a conventional solid-state reaction method at high temperatures. The formation of the compounds was confirmed using X-ray diffraction and energy dispersive X-ray techniques. Using Scherrer's formula and Williamson and Hall's (W–H) method, the average size of the crystallite was found to be 55 nm and 85 nm, respectively. Impedance spectra were measured at temperatures ranging from 553 to 673 K, covering a frequency range of 10 Hz to 1 MHz. The AC conductivity displays frequency-dependent behavior following a variation of the universal power law described by this equation: σAC (ω) = σDC + AωS. By analyzing the plot of the pre-exponent S versus temperature, it was determined that the conduction mechanism in the system could be explained using the correlated barrier hopping model. Parameters such as hopping distance Rω and localized state density N(EF) were calculated. The behavior of permittivity (ε′, ε″) and the loss coefficient tan δ were attributed to Wagner's Maxwell theory of interfacial polarization. Complex electric modulus studies confirmed that the relaxation process was thermally activated. Thermodynamic parameters, including the enthalpy ΔH and the change in entropy ΔS, were calculated. The negative value of ΔS indicated the presence of dipole–dipole interactions and the alignment of molecules in the activated state. [ABSTRACT FROM AUTHOR]

The ceramic K2Ba3(P2O7)2(KBP) sample was successfully synthesized by means of a conventional solid-state reaction and described by means of X-ray diffraction (XRD), transmission electron microscopy, scanning electron microscopy and energy-dispersive spectroscopy as well as infrared techniques. The diffraction (XRD) data indicate that this specimen has an orthorhombic symmetry and belongs to the Pmn21 space group without extra peaks. The infrared spectrum was interpreted on the basis of P2O74− vibrations. By using UV–Vis spectroscopy and the Tauc model, it was obvious that the direct optical band gap of the sample amounts to 3.57 eV. In particular, the studied compound also exhibits optical and semiconducting properties. Basically, the real and imaginary parts of the impedance function and conductivity were investigated in wide temperature and frequency ranges. The angular frequency dependence of AC conductivity is interpreted by using Jonscher's law. The temperature dependence of frequency exponents indicates that the conduction in KBP is insured by the (OLPT) model. From these consequences, it could be concluded that this material may be used for different high-temperature programs. [ABSTRACT FROM AUTHOR]

The ceramic K2Ba3(P2O7)2(KBP) sample was successfully synthesized by means of a conventional solid-state reaction and described by means of X-ray diffraction (XRD), transmission electron microscopy, scanning electron microscopy and energy-dispersive spectroscopy as well as infrared techniques. The diffraction (XRD) data indicate that this specimen has an orthorhombic symmetry and belongs to the Pmn21 space group without extra peaks. The infrared spectrum was interpreted on the basis of P2O74− vibrations. By using UV–Vis spectroscopy and the Tauc model, it was obvious that the direct optical band gap of the sample amounts to 3.57 eV. In particular, the studied compound also exhibits optical and semiconducting properties. Basically, the real and imaginary parts of the impedance function and conductivity were investigated in wide temperature and frequency ranges. The angular frequency dependence of AC conductivity is interpreted by using Jonscher's law. The temperature dependence of frequency exponents indicates that the conduction in KBP is insured by the (OLPT) model. From these consequences, it could be concluded that this material may be used for different high-temperature programs. [ABSTRACT FROM AUTHOR]

Sodium cadmium orthophosphate NaCdPO was prepared by solid-state reaction method at high temperature under air atmosphere. Structural, morphology and electrical properties have been investigated. X-ray powder diffraction analysis indicated that the sample is well crystallized in the orthorhombic maricite structure with Pmnb space group. The composition and morphology of the compound were performed by energy dispersive spectroscopy coupled with scanning electron microscope. Electrical properties were carried out in the frequency range 209 Hz-1 MHz at various temperatures 595-700 K using impedance spectroscopy technique. Nyquist plots analysis revealed the presence of two contributions at different temperatures associated with grain and grain boundary. In order to explain the impedance results an equivalent circuit has been proposed. The AC conductivity was analyzed by Jonscher's power law of frequency ( σ ( ω) ∞ Aω ). At high frequency, the conduction mechanism was well interpreted in term overlapping large polaron tunneling. [ABSTRACT FROM AUTHOR]

Abstract: Synthesis, crystal structure, 13C CP-MAS-NMR analysis and impedance spectroscopy study are reported for a new organic–inorganic hybrid salt, [C7H12N2][ZnCl4], consisting of one 2,4-diammonium toluene cation and one [ZnCl4]2− anion. The Zn atom is in a slightly distorted tetrahedra coordination environment. The structure can be described by the alternation of ionic and organic layers. The cohesion of the material is assured by strong charge-assisted N–H⋯Cl interactions established between ammonium groups and discrete [ZnCl4]2− tetrahedra. Solid state 13C CP-MAS-NMR spectra show seven isotropic resonances, confirming the existence of seven non-equivalent carbon atoms which are consistent with the solid state structure determined by X-ray diffraction. Impedance spectroscopy study, reported for single crystal and powder samples, reveals that the conduction in the material is due to a hopping process along the [100] direction. [Copyright &y& Elsevier]

LiCdVO4 (I) and Li0.75Na0.25CdVO4 (II) are prepared by solid state reaction of stoichiometric mixtures of Li2CO3, Na2CO3, V2O5, and CdO (953 K (I) and 1000 K (II), 12 h). [ABSTRACT FROM AUTHOR]

The synthesis of high-quality thin films through spin coating deposition on meticulously cleaned glass substrates is presented. Optical band gaps E g of both samples using the Kubelka-Munk function are determined. The data analysis uncovers the presence of optical allowed direct transition for A 2 ZnGeO 4 (A = K, Li). Spectroscopic ellipsometry measurements on A 2 ZnGeO 4 (A = K, Li) thin films and an analysis of their optical properties using the Cauchy model are presented. Furthermore, the increase of the thickness of the thin film results in improvements in their optoelectrical parameters, such as electrical conductivity, optical mobility, and optical conductivity. Using the Kubodera and Kobayashi comparative model, the third order nonlinear susceptibility ( χ (3) ) was estimated based on the compounds' high linear absorption of the generated third harmonic wavelength (355 nm). This paper presents remarkable NLO results that reveal potential uses in optoelectronics and photonics., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)