Preparation and Investigation of Structural, Magnetic and Microwave Absorption Properties of Ba0.2Sr0.2La0.6MnO3/MWCNT Nanocomposite in Comparison with Ba0.2Sr0.2La0.6MnO3 in X-band Region

In this research, MWCNT-based nanohybrids made of functionalized multi-walled carbon nanotubes with multi-element magnetic nanocomposites Ba0.2Sr0.2La0.6MnO3/MWCNT were prepared and used to strengthen the intensity and absorbing frequency bandwidth and maximum microwaves absorption in X-band. Initially Ba0.2Sr0.2La0.6MnO3 NPs was synthesized by sol-gel method. Afterwards, the MWCNT was functionalized with carboxylic functional group by acid treating in a mixture of sulfuric/nitric acid in 3:1 ratio (V/V) using ultrasonic irradiation and mechanical stirring simultaneously. The functionalized MWCNT was then coated with these NPs using poly methyl methacrylate (PMMA) in an argon atmosphere furnace. The crystal structures and morphology of synthesized nanoparticles and suitable coating of carbon nanotubes with these nanoparticles were characterized and confirmed by FESEM, XRD, VSM, FTIR analysis. Finally absorbent samples were prepared by dispersion of magnetic NPs and nanocomposite in polyurethane in an ultrasonic bath and the absorption or reflection loss for absorbing samples was investigated at the frequency range of 8.2 – 12.4 GHz. The maximum reflection loss of Ba 0.2Sr0.2La 0.6MnO3 NPs was -14.46 dB at 10.74 GHz with a bandwidth of 1.72GHz (more than –10 dB) and the maximum reflection loss for Ba0.2Sr0.2La0.6MnO3/MWCNT nanocomposite was -22.97 dB at 11.45GHz with a bandwidth of 2.29GHz (more than –10dB). These results indicated that albeit Ba 0.2Sr0.2La 0.6MnO3 NPs has its own microwave absorption properties and could be a good absorber in X-band, but the microwave absorption properties of the hybrid Ba 0.2Sr0.2La 0.6MnO3/MWCNT nanocomposites are significantly enhanced.