α-Fe2O3@CoFe2O4/GO nanocomposites for broadband microwave absorption by surface/interface effects

In this study, α-Fe2O3@CoFe2O4 core­shell nanoparticles were synthesized and decorated on graphene oxide (GO) sheets with two ratios (3:1) and (5:1) for α-Fe2O3@CoFe2O4 to GO. FESEM images indicate a uniform distribution of α-Fe2O3@CoFe2O4 on the surface of GO, especially for (3:1) ratio. The α-Fe2O3@CoFe2O4/GO magnetic nanocomposite exhibits multiple magnetic resonances, strong interfacial polarization, multi reflection and scattering of incident microwaves, thus superior absorption properties. This is due to the structure, which provides various interfaces, high specific surface area, and multiple magnetic components. The microwave absorption properties are evaluated in the frequency range 8–18 GHz (X and Ku bands). Our results show that α-Fe2O3@CoFe2O4/GO (5:1) has the highest reflection loss, −81.24 dB, at 11.98 GHz with a thickness of only 1.4 mm and bandwidth of 3.78 GHz. Interestingly, α-Fe2O3@CoFe2O4/GO (3:1) shows a remarkable broad absorption bandwidth of 8.91 GHz for a thickness of 3.4 mm, having reflection loss, −75.14 dB at 10.25 GHz. The present results confirm that the prepared nanocomposites have promising potential applications in broadband absorption.