Preparation of neat and capped BaFe2O4 nanoparticles and investigation of morphology, magnetic, and polarization effects on its microwave and optical performance

Abstract

In this study, pure BaFe2O4 nanoparticles were prepared using the citrate gel method and then the presence of glucose as a novel organic capping agent on its characteristics was explored. Moreover, neat BaFe2O4 nanostructures were synthesized at 650 °C or 850 °C, which results confirmed the heat treatments have a significant effect on its properties. Besides, microwave absorbing mediums were compared by silicone rubber or Polyvinylidene fluoride (PVDF) polymeric matrices. The Fourier transform infrared (FT-IR) revealed that BaFe2O4 structures at 650 °C or 850 °C, as well as capped nanoparticles at 850 °C were formed without any organic impurities. The results of the vibrating sample magnetometer (VSM) exhibited that the heat treatment at 850 °C led to an increase in the saturation magnetization (Ms) as well as on one hand organic capping agent diminished Ms, on the other hand, enhanced the isotropic magnetic property of the nanoparticles. X-ray powder diffraction (XRD) patterns illustrated pure crystal structure for all three samples with a size of 10.2 nm calculated by the Scherrer equation. Additionally, field emission scanning electron microscopy (FE-SEM) and diffuse reflection spectroscopy (DRS) analysis illustrated that the calcination temperature and organic capping agent respectively changed morphology and band gap of synthesized nanostructures. Finally, Microwave absorption properties were studied using vector network analyzer (VNA). Based on the results, the maximum reflection loss of capped BaFe2O4 at 850 °C/silicone rubber nanocomposite was −82.74 dB at 11.2 GHz with a thickness of 2.5 mm also BaFe2O4 at 650 °C/silicone rubber nanocomposite absorbed 7.39 GHz bandwidth more than 10 dB with a thickness of 2 mm in the x and ku-band frequency.