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The aluminium doped barium hexaferrite BaFe12-xAlxO19 with x =0.0, 1.0, 2.0, 4.0 and 6.0 have been synthesized by the sol-gel method to modify the magnetic properties for technological applications. The crystal structure and phase purity of all the samples have been explored by employing the X-ray diffraction (XRD) technique. It confirms that the sample is nanocrystalline, hexagonal symmetry and all the intense peaks could be indexed to the P63/mmc space group. The obtained lattice parameters from the XRD analysis decrease with the increase in Al3+ content in the samples. The microstructural morphology and particle sizes of all samples were studied by using the Field Emission Scanning Electron Microscopy (FESEM-Hitachi-S4800) technique. The magnetic hysteresis (M-H) loops measurement has been carried out at room temperature by employing the vibrating sample magnetometer (VSM) over a field range of +20 kOe to -20 kOe. The magnetic hysteresis (M-H) loops revealed the ferromagnetic (hard magnetic materials) nature of the samples and, analyzed by using the Law of Approach to Saturation. [ABSTRACT FROM AUTHOR]

Bi1-xLaxFe1-xMnxO3 ceramics with x = 0.00, 0.05, 0.10 and 0.20 were synthesized by the tartaric acid modified sol-gel technique with required optimization. The co-substitution suppresses the impurities phases in bismuth ferrite which is usually observed. It was observed that the composition-driven structural transition from rhombohedral (R3c space group) to orthorhombic symmetry (Pbnm space group) plays an important role in modifying the dielectric properties of bismuth ferrite. The dielectric constant was found to be increased in La and Mn co-substituted BiFeO3 due to significant large off-center movement of Fe3+ ions in the oxygen octahedra. The dispersion of dielectric constant in the frequency range of 100 Hz to 1 MHz has been analyzed by employing the modified Debye's function which suggests the contribution of multiple charge carriers in the dielectric relaxation. [ABSTRACT FROM AUTHOR]

(1-x)Cobalt ferrite-(x)reduced graphene oxidenanocomposites with x=0, 0.1, 0.2 and 0.3 were prepared by the ultrasonic method. The crystal symmetry modification due to reduced graphene oxide and cobalt ferrite interaction has been studied by employing the X-ray diffraction technique. Morphology of the samples was studied by the Field emission scanning electron microscopy (FE-SEM). Study on electrical properties of the cobalt ferrite-reduced graphene oxide nanocomposites explores the possible application of these composites as anode material. Impedance decreases with an increase in frequency as well as temperature, which supports an increase in ac electrical conductivity. The modified Debye relaxation model can explain the behavior of impedance in cobalt ferrite-reduced graphene oxide nanocomposites. [ABSTRACT FROM AUTHOR]

Bi1-xLaxFe1-xMnxO3 ceramics with x = 0.00, 0.05, 0.10 and 0.20 were synthesized by the tartaric acid modified sol-gel technique with required optimization. The co-substitution suppresses the impurities phases in bismuth ferrite which is usually observed. It was observed that the composition-driven structural transition from rhombohedral (R3c space group) to orthorhombic symmetry (Pbnm space group) plays an important role in modifying the dielectric properties of bismuth ferrite. The dielectric constant was found to be increased in La and Mn co-substituted BiFeO3 due to significant large off-center movement of Fe3+ ions in the oxygen octahedra. The dispersion of dielectric constant in the frequency range of 100 Hz to 1 MHz has been analyzed by employing the modified Debye's function which suggests the contribution of multiple charge carriers in the dielectric relaxation. [ABSTRACT FROM AUTHOR]

The PVDF-CoFe1.5Cr0.5O4 (PVDF-CFCO5) nanocomposite films are synthesized with different weight % of CoFe1.5Cr0.5O4 as filler in PVDF matrix. X-ray diffraction pattern detected the existence of α and β phases and, also validate the result by Fourier transform infrared microscopy. The inclusion of CFCO5 nanoparticles in the polymer medium initiates the alteration of phase between α and β and, offers the nanocomposites greater mobile charge carriers which contribute in the interfacial polarization. The dielectric properties of PVDF-CFCO5 films have superior dielectric constant and considerably a lesser dissipation factor (tan δ) as compared to pure PVDF as well as pure cobalt ferrite. The dielectric constant decreases at higher concentrations of CFCO5 due to agglomeration of the nanoparticles. Thus, their controlled inclusion in a polymer medium to get improved electrical properties will have a significant impact to the present day research. The enhanced dielectric constant of PVDF-CFCO5 film can be utilized for wide applications such as dielectric material for capacitor application. [ABSTRACT FROM AUTHOR]

Cobalt ferrite of different average crystallites (from nanocrystallite to micro crystallites) has been prepared by the Sol-Gel Method. The X-ray diffraction (XRD) analysis confirms the cubic spinel phase with no trace of impurity phases. The effect of annealing temperature on micro structure and electric transport properties as a function of frequency and temperature has been studied. It is observed that the electric impedance and conductivity are strongly dependent on grain size. The impedance spectroscopic study is employed to understand the electrical transport properties of cobalt ferrite. [ABSTRACT FROM AUTHOR]

Effect of lattice distortion on diffuse phase transition in BNBTO solid solutions near Morphotropic phase boundary (MPB) has been investigated. Solid solutions of (Bi0.5Na0.5)1−xBaxTiO3 (with mole % of x= 0.04, 0.05, 0.06, 0.07 and 0.08) were prepared by the planetary ball mill method in ethanol medium. Rietveld refinement technique with rhombohedral (R3c) and tetragonal (P4bm) crystal symmetry has been employed for structural as well as phase analysis of the solid solutions. Both rhombohedral and tetragonal lattice distortion (c/a) tends toward the pseudo-cubic crystal symmetry with the increase of mole fraction of Ba2+ near MPB (x= 6 mole %). Also, the average crystallite size and grain size decrease with increase of mole fraction of Ba2+ in BNT ceramic are due to larger ionic radius of Ba2+ and grain boundary pinning process in the solid solutions respectively. Additionally, depolarization temperature (Td) and maximum temperature (Tm) reduces due to the lattice distortion of both the phases in BNBTO solid solutions, which is explained extensively. Significant increase of dielectric constant has been observed near MPB composition (x=6%) in BNBTO solid solutions. [ABSTRACT FROM AUTHOR]