SUMMARYGrain-size dependence of electromagnetic absorbing characteristics for composite materials made of Ni-Zn ferrite and SiO 2 was investigated using SiO 2 with various grain sizes (29 µm, 30 nm, 12 nm, and 7 nm). The absorption characteristics of ferrite composites using SiO 2 with an average grain size of 30, 12, or 7 nm were improved compared with those of ferrite composites using SiO 2 with an average grain size of 29 µm in the low-frequency region. Furthermore, the grain size dependence of the absorption characteristics for composite materials of Mn-Zn ferrite with an average grain size of 130 nm and SiO 2 with an average grain size of 29 µm was investigated. The absorbing center frequency shifted to a higher frequency region than that of Mn-Zn ferrite.
Grain-size dependence of electromagnetic absorbing characteristics for composite materials made of Ni-Zn ferrite and SiO2 was investigated by using SiO2 with various grain sizes (29µm, 30nm, 12nm, 7nm). The absorption characteristics of ferrite composites using SiO2 of the average grain size 30nm, 12nm or 7nm were improved compared with those of ferrite composites using SiO2 of the average grain size 29µm in the low frequency region. Furthermore, grain size dependence for composite materials of Mn-Zn ferrite with the average grain size of 130nm and SiO2 with the average grain size of 29µm was investigated. The absorbing center frequency was shifted to the higher frequency region compared with that of Mn-Zn ferrite.
It is found through simulation study that electromagnetic wave absorbers made of composites of Ni-Zn ferrite and SiO 2 particles, which are isolated in the continuous medium of Ni-Zn ferrite, show absorption in the frequency regions both below and above 1 GHz [1]. The spray method is proposed to realize such composites in this study. It is confirmed by XRD and electromagnetic characteristics that thin films of Ni-Zn ferrite can be coated on the surfaces of SiO 2 particles by the spray thin film deposition method and the measured complex permeability is close to that calculated using the isolation model of SiO 2 particles in the Ni-Zn ferrite medium.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.