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Fabrication, Structure and Dielectric Properties of Fe2O3 / MgO Composites
Bushra A. Hasan, Duaa A. Uamran and Hiba H. Issa
Fe2O3 / MgO composites with various ratios (90/10,80/20,70/30,60/40 and 50/50 %wt.) were synthesized. Their structure was determined using the X-ray diffractometer. The observed X- Ray patterns showed that the prepared composites were polycrystalline with rhombohedral Hematite (α-Fe2O3) whereas the preferred planes for crystal growth are (104) and (110).The dielectric properties of the Fe2O3 / MgO, with various ratios, were studied as function of frequency over the range (50Hz – 1MHz). The conductivity as function to frequency σa.c (ω) obey the power law relation σa.c (ω) =Aωs where the factor s was found to be in the range 0.329-0.491. The dielectric constant is increasing; but not in a regular way, with the increasing MgO content. The dielectric loss increases with increasing the MgO ratio up 4%wt. and then decreases. The relaxation time was found also to increase the increasing MgO content, showing a decrease of conductivity and a slowing of the charge carriers movement. The polarizability (α) was measured from the plot of dielectric constant versus the dielectric loss variation. It was found that it increases from 0.112 to 0.234 with the increasing MgO content from 10 to 50 wt. % .
Keywords: Dielectric properties of Fe2O3/MgO composites. Polarizability, conductivity, dielectric loss