Preparation and characterization of Ba_0.2Sr_0.2La_0.6MnO₃ nanoparticles and investigation of size & shape effect on microwave absorption

Highlights: • Hydrothermal synthesis of Ba_0.2Sr_0.2La_0.6MnO₃ performed in the presence of PMMA. • Shape and size-controlled synthesis of NPs over the range 15–50 Nm was explored. • Investigation of shape and size effect of NPs on microwave absorption properties. - Abstract: In this paper, the design and characterization of a radar absorbing material (RAM) was investigated at microwave frequency. Ba_0.2Sr_0.2La_0.6MnO₃ magnetic nanoparticles was synthesized thru a facile hydrothermal method in the presence of polymethyl methacrylate (PMMA) and the possibility of shape and size-controlled synthesis of nanoparticles (NPs) over the range 15–50 Nm was also explored. Afterward, the effect of shape and size of the synthesized Ba_0.2Sr_0.2La_0.6MnO₃ NPs on microwave absorption properties was investigated in KU-band. The crystal structures and morphology of as-synthesized nanoparticles were characterized and confirmed by FESEM, XRD, VSM, FTIR analysis. The RAM samples were prepared by dispersion of magnetic NPs in silicone rubber in an ultrasonic bath. The maximum reflection loss (RL) values NPs were 12.04 dB at 14.82 GHz and a broad absorption band (over 1.22 GHz) with RL values <−10 dB are obtained and the maximum reflection loss (RL) values of decrease and shaped NPs were 22.36 dB at 14.78 GHz and a broad absorption band (over 2.67 GHz) with RL values <−10 dB are obtained. The results indicated that the particle size and shape play a major role on the absorption properties of the composites in the 12.4–18 GHz frequency range. It is observed that microwave absorption properties increased with the decrease in average particle size of NPs.