Mohamed Ali Ahmed (M.A.Ahmed)

Nanometric multiferroic namely Ag doped (BiFeO3) was synthesized using flash auto combustion technique and glycine as a fuel. Single phase rhombohedral-hexagonal perovskite structure was obtained by annealing at 550 C, as determined from XRD. High resolution transmission electron microscope (HRTEM) clarifies the hexagonal platelet shape with size 17.9 nm. Maximum room temperature AC conductivity was obtained at Ag content of x = 0.10. The results of this study promote the use of such multiferroic in solid oxide fuel cell applications. © 2013 Elsevier Ltd. All rights reserved.

Single-phases of the spinel nanoferrites Zn0.5Co 0.5Al0.5R0.04Fe1.46O4; R=Sm, Pr, Ce and La, were synthesized using the flash auto combustion method. X-ray diffraction (XRD) results indicated that doping nanoferrites with small concentrations of rare earth elements (RE) allowed their entrance to the spinel lattice. Transmission electron microscope (TEM) images revealed that doping with different RE elements resulted in the formation of different nanometric shapes such as nanospheres and nanowires. Doping with Sm3+ and Ce 3+ resulted in the formation of nanospheres with average diameter of 14 and 30 nm respectively. In addition to the granular nanospheres, doping with Pr3+ and La3+ resulted in the formation of some nanowires with different aspect ratios (average length of ≈100 nm and diameter of ≈9 nm) and (average length of ≈150 nm and outer diameter of ≈22 nm) respectively. At fixed temperature, the Ac conductivity (σ) increased as the RE ionic radius increases except for Ce, due to the role of valance fluctuation from Ce3+ to Ce4+ ions. La- and Pr-doped nanoferrites showed the highest ac conductivity values, which is most probably due to the presence of large numbers of nanowires in these two types of ferrites. For all entire samples, the effective magnetic moment (μeff) decreased, while the Curie temperature (TC) increased as the RE ionic radius increases. The synthesized rare earth nanoferrites showed promising results in purifying colored wastewater. La-doped ferrite was capable for up-taking 92% of the dye content, followed by Pr-doped ferrite, which adsorbed 85% of the dye, while Sm- and Ce-doped ferrites showed lower dye removal efficiency of 80% and 72% respectively. High dye uptake shown by La- and Pr-doped ferrites is most probably due to the presence of nanowires and their higher Ac conductivity values. These excellent results were not previously reported. © 2013 Published by Elsevier B.V.

Nanometric multiferroic namely Ag doped (BiFeO3) was synthesized using flash auto combustion technique and glycine as a fuel. Single phase rhombohedral-hexagonal perovskite structure was obtained by annealing at 550 C, as determined from XRD. High resolution transmission electron microscope (HRTEM) clarifies the hexagonal platelet shape with size 17.9 nm. Maximum room temperature AC conductivity was obtained at Ag content of x = 0.10. The results of this study promote the use of such multiferroic in solid oxide fuel cell applications. © 2013 Elsevier Ltd. All rights reserved.

Nanometric multiferroic namely Ag doped (BiFeO3) was synthesized using flash auto combustion technique and glycine as a fuel. Single phase rhombohedral-hexagonal perovskite structure was obtained by annealing at 550 C, as determined from XRD. High resolution transmission electron microscope (HRTEM) clarifies the hexagonal platelet shape with size 17.9 nm. Maximum room temperature AC conductivity was obtained at Ag content of x = 0.10. The results of this study promote the use of such multiferroic in solid oxide fuel cell applications. © 2013 Elsevier Ltd. All rights reserved.

Single-phases of the spinel nanoferrites Zn0.5Co 0.5Al0.5R0.04Fe1.46O4; R=Sm, Pr, Ce and La, were synthesized using the flash auto combustion method. X-ray diffraction (XRD) results indicated that doping nanoferrites with small concentrations of rare earth elements (RE) allowed their entrance to the spinel lattice. Transmission electron microscope (TEM) images revealed that doping with different RE elements resulted in the formation of different nanometric shapes such as nanospheres and nanowires. Doping with Sm3+ and Ce 3+ resulted in the formation of nanospheres with average diameter of 14 and 30 nm respectively. In addition to the granular nanospheres, doping with Pr3+ and La3+ resulted in the formation of some nanowires with different aspect ratios (average length of ≈100 nm and diameter of ≈9 nm) and (average length of ≈150 nm and outer diameter of ≈22 nm) respectively. At fixed temperature, the Ac conductivity (σ) increased as the RE ionic radius increases except for Ce, due to the role of valance fluctuation from Ce3+ to Ce4+ ions. La- and Pr-doped nanoferrites showed the highest ac conductivity values, which is most probably due to the presence of large numbers of nanowires in these two types of ferrites. For all entire samples, the effective magnetic moment (μeff) decreased, while the Curie temperature (TC) increased as the RE ionic radius increases. The synthesized rare earth nanoferrites showed promising results in purifying colored wastewater. La-doped ferrite was capable for up-taking 92% of the dye content, followed by Pr-doped ferrite, which adsorbed 85% of the dye, while Sm- and Ce-doped ferrites showed lower dye removal efficiency of 80% and 72% respectively. High dye uptake shown by La- and Pr-doped ferrites is most probably due to the presence of nanowires and their higher Ac conductivity values. These excellent results were not previously reported. © 2013 Published by Elsevier B.V.

Single-phases of the spinel nanoferrites Zn0.5Co 0.5Al0.5R0.04Fe1.46O4; R=Sm, Pr, Ce and La, were synthesized using the flash auto combustion method. X-ray diffraction (XRD) results indicated that doping nanoferrites with small concentrations of rare earth elements (RE) allowed their entrance to the spinel lattice. Transmission electron microscope (TEM) images revealed that doping with different RE elements resulted in the formation of different nanometric shapes such as nanospheres and nanowires. Doping with Sm3+ and Ce 3+ resulted in the formation of nanospheres with average diameter of 14 and 30 nm respectively. In addition to the granular nanospheres, doping with Pr3+ and La3+ resulted in the formation of some nanowires with different aspect ratios (average length of ≈100 nm and diameter of ≈9 nm) and (average length of ≈150 nm and outer diameter of ≈22 nm) respectively. At fixed temperature, the Ac conductivity (σ) increased as the RE ionic radius increases except for Ce, due to the role of valance fluctuation from Ce3+ to Ce4+ ions. La- and Pr-doped nanoferrites showed the highest ac conductivity values, which is most probably due to the presence of large numbers of nanowires in these two types of ferrites. For all entire samples, the effective magnetic moment (μeff) decreased, while the Curie temperature (TC) increased as the RE ionic radius increases. The synthesized rare earth nanoferrites showed promising results in purifying colored wastewater. La-doped ferrite was capable for up-taking 92% of the dye content, followed by Pr-doped ferrite, which adsorbed 85% of the dye, while Sm- and Ce-doped ferrites showed lower dye removal efficiency of 80% and 72% respectively. High dye uptake shown by La- and Pr-doped ferrites is most probably due to the presence of nanowires and their higher Ac conductivity values. These excellent results were not previously reported. © 2013 Published by Elsevier B.V.

New techniques are used to synthesis and characterize 0.5BaTiO 3/0.5Ni0.5Zn0.5Fe2O4; (BTO/NZF) multiferroic nanocomposite. Improved citrate autocombustion preparation technique is used to synthesis ferromagnetic and ferroelectric phases of the investigated nanocomposite. Atomic force microscope (AFM) is one of the important tools for imaging, measuring, and manipulating matter at the nanoscale. AFM is used at different sample areas to confirm the data obtained from scanning electron microscope (SEM) and transmission electron microscope (TEM). Moreover AFM gives 3D visualization for the surface texture and roughness showing the morphology of the two distinguishes phases. The traditional characterizations techniques have been used such as X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) to identify the formation of the two individual phases separately and to study the chemical composition of the prepared nanocomposite respectively. © 2013 Elsevier B.V. All rights reserved.

The generation of nanoparticles using pulsed laser ablation has inherent advantages compared to conventional methods, like the purity and stability of the fabricated nanoparticles, aerosols and colloids. This study addresses the influence of laser parameters such as laser fluence, laser wavelength as well as focusing condition of laser beam on the size and morphology of the gold nanoparticles prepared in de-ionized water by pulsed laser ablation. The optimum conditions at which gold nanoparticles are obtained with controllable average size have been reported as these parameters affected the size, distribution and absorbance spectrum. The effect of laser fluence was studied. The laser fluences were divided into three regions (low, middle and high). A noteworthy change was observed at each region. At low fluences, the size of the nanoparticles decreases as the fluence increases to a certain critical value after which the size of the nanoparticles increases as the fluence increases. Also a significant change in the size distribution of the gold nanoparticles was noticed during the variation of the focusing conditions at gold-water interface. © 2012 Elsevier Ltd.

Flash auto combustion method was successfully used to synthesize nanoparticles of Zn0.5Co0.5Al0.5Fe 1.46-La0.04O4. High resolution transmission electron microscopy (HRTEM) specified the formation of granular nanospheres beside an intermediated phase of nanowires. Polymer-blended magnetic materials were obtained using poly(vinyl pyrrolidone) (PVP), poly(vinyl alcohol) (PVA), poly(vinyl acetate) (PVAc) and Polyethylene Glycol (PEG) as capping agents. This coating strategy controls the agglomeration of ferrite nanoparticles, and produces a well-designed core-shell nano-assembly with enhanced physical properties. XRD and HRTEM confirmed the formation of ferrite as a core surrounded by various polymeric shells. The nanocomposite with PVP shell resulted in increased ac conductivity (σ) of about four orders of magnitude higher than that recorded for the pure ferrite. Curie temperature (Tc) decreased from 703 K as recorded for the pure ferrite to less than 440 K for the core-shell nanocomposites containing PVA and PVAc. All prepared samples succeeded in purifying inked-water with high efficiency. Zn0.5Co0.5Al0.5Fe1.46-La 0.04O4 up-took 76% of the dye content, while the dye-removal efficiency was increased to 90% when Zn0.5Co 0.5Al0.5Fe1.46La0.04O 4/PVP core-shell nanocomposite was applied. These novel results indicate that such series of core-shell nanocomposites are promising candidates in industrial applications such as purifying and recycling of industrial waste water. Moreover, this study emphasized that polymers are good additive to ferrites when blended in the form of core-shell nanocomposite structure. © 2013 Elsevier B.V. All rights reserved.