Broadband electromagnetic wave absorption of Ni0.5Zn0.5Nd0.04Fe1.96O4 ferrites modified by nano-silver particles

Ferrite materials have the potential to become excellent absorbing materials due to their high magnetic loss and good impedance matching. However, the disadvantages of high density and lack of dielectric loss capability limit its application. Herein, we used the citric acid sol-gel method and the self-propagating combustion method to prepare neodymium-doped nickel-zinc ferrite (NZNF), then the target effect of Sn²⁺ and an improved electroless silver plating process was used to plate a layer composed of silver nanoparticles (Ag NPs) with strong dielectric loss on the NZNF, and a magnetic/dielectric composite material (NZNF@Ag) with a heterogeneous structure was prepared. The number and particle size of Ag NPs on the surface of NZNF can be precisely controlled, thereby greatly enhancing the dielectric loss capability with little impact on the magnetic loss. The huge difference in conductivity between conductors and semiconductors promotes the occurrence of polarization at the heterogeneous interface and significantly enhances the electromagnetic wave absorption ability of the composite material. In the 2–18 GHz frequency band, the best sample can obtain an effective bandwidth of 6.82 GHz when the matching thickness is 2.1 mm. Combining conductors with semiconductor materials to obtain significantly enhanced interfacial polarization provides a new idea for improving the performance of wave absorbing materials.