[en] Herein, a scalable method is developed to fabricate carbon nanotube (CNT)/Fe₃O₄(a)C composites, in which the crystallization and morphology of the carbon shell on the surface of Fe₃O₄ nanoparticles can be controlled by manipulating the synthesis conditions of chemical vapor deposition technology. Owing to the synergic dissipation effect of the core-shell structure, as well as the excellent conductive loss induced by the CNT skeleton, the CNT/Fe₃O₄(a)C composite shows a minimum reflection loss of -50.1 dB at 9.7 GHz and an effective bandwidth of 4.6 GHz. This study provides new insight into preparing core-shell-structured microwave absorbers with excellent performance. (author)