Abstract
Mn-Sn-Dy-substituted and pure strontium ferrite, were prepared from metal nitrates and citric acid through citrate sol–gel method. The phase composition, microstructure, coercivity, and microwave absorption properties of the particles were investigated by means of X-ray diffraction, transmission electron microscopy (TEM), vibrating sample magnetometry and a vector network analyzer. The ferrite–polymer composites with different ferrite ratios of, 60%, 70% and 80% in acrylic resin matrix were prepared. The microwave absorption properties of these composites were investigated in the frequency range of 12–20 GHz. The results showed that the composite with 70% ferrite content has shown a minimum reflection loss of -28 dB at 15.7 GHz with the -15 dB bandwidth over the extended frequency range of 14.3–20 GHz for an absorber thickness of 1.6 mm. A minimum reflection loss of -38 dB was obsevred at 18.2 GHz for composite with 80% ferrite. Based on this study it can be argued that such powders are very useful in military applications such as RCS (Radar Cross Section ) reduction, camouflaging of the target and prevention of EMI (Electromagnetic Interference), etc.
Keywords: Nano-crystalline materials, Magnetic materials, Magnetic properties, Chemical synthesis