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Structural, optical, and dielectric studies of LaFe1?xMoxO3 (x?=?0.0, 0.5) perovskite materials
摘要： The structural, optical, and dielectric properties of LaFe1?xMoxO3 (x = 0.0, 0.5) synthesized by the sol–gel method were investigated by X-ray diffraction (XRD), Raman scattering, and impedance spectroscopy. XRD analysis revealed that the x = 0.5 compound is single-phase and orthorhombic, with space group Pbnm, similar to the parent x = 0.0 compound but with larger lattice parameters and/or a larger unit-cell volume. The Raman scattering spectra revealed local lattice distortions in the x = 0.5 compound and spin–phonon coupling related to the magnetic transition (Néel) temperature. The impedance data were well fitted with an R(R1-CPE1)//(R2-CPE2) equivalent electrical circuit, demonstrating the contributions of both grains and grain boundaries. The temperature (300–500 K) and frequency (100 Hz–1 MHz) dependences of the dielectric properties showed that Mo substitution adversely affected the dielectric parameters.
关键词： X-ray diffraction,LaFe1?xMoxO3,impedance spectroscopy,Raman scattering,sol–gel method,dielectric properties
更新于2025-09-04 15:30:14
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Studies on growth and characterization of (E)-N′-[4-(dimethylamino) benzylidene]-4-hydroxybenzohydrazide hemihydrate: a nonlinear optical material
摘要： Hydrazone compound (E)-N′-[4-(dimethylamino) benzylidene]-4-hydroxybenzohydrazide hemihydrate (DMABHBH) was synthesized and single crystals of DMABHBH were grown by solvent evaporation method at room temperature. Molecular structure of DMABHBH compound was confirmed by 1H and 13C nuclear magnetic resonance techniques. The presence of functional groups was confirmed by Fourier transform infrared and FT Raman spectral analyses. The X-ray crystal structure was elucidated at 173 K by single crystal X-ray diffraction and the results were compared with the corresponding values obtained at 298 K. The compound crystallizes in the chiral monoclinic space group P21. Mechanical stability of the grown crystals was estimated from the Vicker’s microhardness test. Powder second harmonic generation efficiency of DMABHBH is about 1.1 times that of potassium dihydrogen phosphate. DMABHBH is found to show optical limiting behavior at high input light intensities, the third order nonlinear optical absorption coefficient measured using open aperture Z-scan studies, is 0.95 × 10?11 m/W. Anti-bacterial activity was studied using the well and disc diffusion methods.
关键词： X-ray diffraction,Mechanical properties,Nonlinear optical material,Thermal analysis,Antibacterial activity,Hydrazone,Crystal growth
更新于2025-09-04 15:30:14
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Point defect chemistry of donor-doped bismuth titanate ceramic
摘要： This communication reports on the defect chemistry at room temperature of barium (Ba) doped bismuth titanate (Bi4Ti3O12), emphasizing the influence of the point defects on its electrical properties. Pure and Ba doped Bi4Ti3O12 were prepared by a conventional solid-phase reaction technique. The addition of Ba into the crystal structure of Bi4Ti3O12 was monitored by X-ray diffraction measurements combined with Rietveld refinement studies where it was determined that Ba occupies the bismuth (Bi) lattice sites as well as the presence of oxygen vacancies (V??O). The characterization of the point defects was carried out using impedance and electron spin resonance spectroscopies where the results support the models of compensation mechanisms dominated by electrical positive charges (h?) and oxygen vacancies (V??O).
关键词： defect chemistry,X-ray diffraction,Rietveld refinement,impedance spectroscopy,solid-phase reaction,barium doped bismuth titanate,electron spin resonance spectroscopy,electrical properties,oxygen vacancies
更新于2025-09-04 15:30:14