Microwave absorption and electromagnetic interference shielding properties of Li-Zn ferrite-carbon nanotubes composite

The Li0.3Zn0.4Fe2.3O4 ferrite (LiZn) was synthesized by sol-gel method. A uniform mixture of carbon nanotubes and Li0.3Zn0.4Fe2.3O4 nanoparticles (LiZn@CNT) was obtained by a simple mechanical mixing method. The presence of carbon nanotubes in the sample LiZn@CNT was confirmed by the analysis of XRD and TEM. Doping carbon nanotubes in the ferrite increased the permittivity, dielectric loss and attenuation constant, leading to the appearance of relaxation process in the sample LiZn@CNT. For the Li0.3Zn0.4Fe2.3O4 ferrite with the thickness of 5 mm, the minimum reflection loss (R-L) and the absorption bandwidth with R-L below -10 dB can reach -34 dB and 5.2 GHz, respectively. The sample LiZn@CNT showed high shielding effectiveness (maximum value 92 dB), and more than 99.8% of electromagnetic waves can be shielded in the frequency range of 0.2-20 GHz, indicating that the composite can be used as an electromagnetic shielding material.

Automated summary

In this study, Li0.3Zn0.4Fe2.3O4 ferrite (LiZn) was synthesized using sol-gel method, and a uniform mixture of carbon nanotubes and Li0.3Zn0.4Fe2.3O4 nanoparticles (LiZn@CNT) was obtained through a simple mechanical mixing method. The addition of carbon nanotubes increased the permittivity, dielectric loss, and attenuation constant of the ferrite, leading to the appearance of relaxation process in the sample LiZn@CNT. The LiZn@CNT composite exhibited high shielding effectiveness, with over 99.8% of electromagnetic waves shielded in the frequency range of 0.2-20 GHz.