According to Chen and coworkers, the composite is characterized by a "strong dipole polarization in the biochar matrix under EM waves, which further enhanced the dielectric loss of the absorbers" (Chen et al., and references therein). "The ID/IG ratio increased distinctly as the carbonization temperature increased", and this "could be attributed to the complete pyrolysis of organic components in the Fe3O4@SP precursors" (Chen et al., 2023). In , where FexOy@Biochar composite materials are studied for high-efficiency microwave absorption, we can find an analysis of the ID/IG ratio too. Being the analysis regarding the D and G peaks, the Raman spectra are not shown below 500 cm -1 .