High-frequency magnetic properties of FeNi₃-SiO₂ nanocomposite synthesized by a facile chemical method

Monodisperse core-shell structured FeNi₃-SiO₂ composite nanoparticles (NPs) were synthesized by a facile hydrazine reduction combined modified Stöber method. SEM and TEM analysis shows that FeNi ₃ cores are composed of small primary nanocrystals and are coated by amorphous SiO₂ layer. As-prepared FeNi₃-SiO₂ nanocomposites exhibit typical soft magnetic properties. The permeability spectra vary with the contents of SiO₂. When the SiO₂ content is 10 wt%, the real part μ′ of the permeability reaches about 10 and is almost independent of frequency in the frequency range up to 1 GHz. And the imaginary part μ″ remains very low. This paper presents a facile approach to fabrication of novel soft magnetic materials for high-frequency applications.