Assembling of the novel Sm2O3@Co magnetic composites for highly efficient electromagnetic wave absorption

Magnetic metals have attracted extensive attention in microwave absorption for comprehensive merits of high magnetic loss and suitability for mass productions. Nevertheless, the applications have been limited by shortcomings of high conductivity and inadequate impedance matching. In this study, we have successfully synthesized a biphasic magnetic Sm2O3@Co composite through a facile one-step precipitation method. The resultant features a well-designed structure with spherical cores and flaky shells, exhibiting highly-tunable absorption performance over 2–18 GHz. Particularly, under 20 wt% filling ratio with paraffin, the Sm2O3@Co composite achieved minimum reflection loss (RLmin) of −30.1 dB and effective absorbing bandwidth (EAB) of 6.22 GHz at only 1.7 mm. The dielectric and magnetic losses could be easily modulated by simply changing the induced Co ratios. Through a systematic study, the microwave absorption mechanisms of the Sm2O3@Co magnetic composite have been comprehensively elucidated. This research offers a fresh perspective on developing highly efficient electromagnetic wave absorbents based on traditional magnetic metals.