A Novel Method to Synthesize Co/Fe₃O₄ Nanocomposites with Optimal Magnetic and Microwave Performance

The magnetic interactions between neighboring magnetic nanoparticles make the synthesis of nanocomposites made of two kinds of magnetic nanoparticles extremely difficult. In this paper, to achieve an effective nanocomposite of Co and Fe₃O₄ nanoparticles, a special urchin-like Co nanomatrix was used to prepare the Co/Fe₃O₄ nanocomposites. The Fe₃O₄ nanoparticles are evenly embedded into the branches of the C_O clusters, bringing the two types of particles into close contact and ensuring the optimal magnetic and microwave properties. The electromagnetic (EM) parameters at 1-18 GHz and the magnetic loss tangents can be effectively modulated, and the absorption frequency bands of the EM waves are shifted to the X-Ku bands (8-18 GHz) from the S-C bands (2-8 GHz) after the Fe₃O₄ nanoparticles are compounded.