Doped Hexaferrites for EMI Suppression Prepared Using Tartaric Acid

Strontium hexaferrites, doped with varying Co-Zr content (x) are synthesized by sol-gel auto-combustion route using tartaric acid as fuel. The effect of calcination temperature (500-1000°C) on the structure, morphology and magnetic properties has also been studied for x=0.2 and 800°C has been found to be the most suitable temperature with the best magnetic properties. Doping results in MS and Mr increase up to x=0.4 whereas HC decreases continuously up to 1.0 dopant level. An average crystalline size of 36.47nm is observed. Electromagnetic characterization of the prepared ferrites shows an increase in the imaginary parts of permittivity and permeability in Ku-band with doping. Ferrites with x = 0.2, 0.8 and 1.0 have appropriate reflection loss (less than -10 dB) and bandwidth (2.35GHz, 1.46GHz and 2.9GHz respectively) in Ku-band, hence can be used as effective absorbers in suppression of electromagnetic interference for defense and communication purposes. Impedance matching condition as well as the lossy nature of ferrites, both play significant role in deciding the absorption properties of hexaferrites.