Shereef Fareed | National Research Institute Of Astronomy And Geophysics Nriag (original) (raw)

Shereef Fareed

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National Research Institute Of Astronomy And Geophysics Nriag

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Papers by Shereef Fareed

Applied Physics A

Nano-crystalline bismuth manganese oxide Bi2Mn4O10 was prepared from Bi2O3 and MnO2 by mechanoche... more Nano-crystalline bismuth manganese oxide Bi2Mn4O10 was prepared from Bi2O3 and MnO2 by mechanochemical technique at different milling times followed by heat treatment at 1073 K. The crystal structural were obtained using X-ray diffraction (XRD) and TEM. We obtained the variation of the crystallite size and micro-strain with milling time. The magnetic parameters include the saturation magnetization, coercivity and squareness ratio were obtained by vibrating sample magnetometer (VSM). Each of the coercive field, Squareness ratio and saturation magnetization increased with increasing the milling time. The electrical conduction of the prepared samples was evaluated by AC conductivity measurements at different temperature, the dielectric parameters were plotted against temperature at different frequencies. The conduction mechanism is described by the correlated barrier hopping model (CBH). The recoverable energy density and loss energy was obtained to calculate the storage energy efficie...

Journal of Materials Science: Materials in Electronics

Bismuth and manganese oxides were mixed as source-materials using the mechanochemical technique f... more Bismuth and manganese oxides were mixed as source-materials using the mechanochemical technique followed by heat treatment to prepare the phase Bi2Mn4O10. The X-Ray Diffraction (XRD) analysis was carried out to obtain the formed phases during the mechanochemical process. Bismuth manganese oxide phase with the chemical formula Bi2Mn4O10 was formed at heat treatment 1073 K and was partially decomposed to γ-Bi12.8O19.2 and α-Mn2O3 after 5 h of milling time. The variation of the crystallite size is obtained at different milling time (1 h, 5 h, 10 h, 15 h, 30 h and 50 h). The temperature dependency of the DC electrical conductivity was observed at different milling times in the temperature range 300–425 K for the samples milled at 5 h, 10 h, 30 h and 50 h. The temperature dependency (300–4 80 K) of the thermoelectric power/Seebeck coefficient (S) and its modulus variation with milling time were observed; the modulus varied in the range (45 µV/K-277 µV/K). The concentration of manganese i...

Production of nanomaterials by mechanochemical synthesis is one of the important modern methods i... more Production of nanomaterials by mechanochemical synthesis is one of the important modern methods in new technology. Mechanochemical technique followed by heat treatment has been used to produce bismuth-manganese oxide from bismuth oxide and manganese dioxide. X-Ray Diffraction (XRD) analysis is conducted evaluate the structure changes during the mechanochemical process. Structure transformation from crystalline to complete amorphous phase was observed after short time of milling. The amorphization mechanism and reaction kinetics are examined in the light of the processing parameters and materials composition. Interdiffusion and distraction of the long rang order structure are the proposed mechanisms for amorphization. Bismuth manganese oxide phase with chemical formula Bi2Mn4O10 was formed after heat treatment at 1073 K. Bi2Mn4O10 partially decomposed to γ-Bi12.8O19.2 and α-Mn2O3. Crystallite size (47.6–102.4 nm) of the formed phases after heat treatment is significantly affecting th...