A comparison study of two different methods to synthesize magnetic slurry for the fabrication of magnetic films

A new spiral thin-film inductor structure is designed, in which the insulating magnetic thin film takes the places of both the insulating layer and the magnetic layer in the traditional structure. For the fabrication of the insulating magnetic film, a magnetic slurry which is a soft magnetic composite composed of organic polymer and nano Fe₃O₄ particles was synthesized. The magnetic slurry was synthesized by chemical co-precipitation method and microemulsions, respectively. Fe₃O₄ particles with a grain size of 20 nm tends to agglomerate and is constrained by the network of silicon gel in the first slurry prepared via co-precipitation. While in the microemulsions, water-soluble organic material disperses the nanoFe₃O₄ whose size lays in the range of 6-15 nm. The two kinds of magnetic slurries have different magnetic susceptibilities, which is 110 cm³/mol, and 344 cm³/mol, respectively. The surface of the film fabricated with the microemulsions slurry is smooth. In contrast, there are a lot of flaws for the film derived from the co-precipitated slurry. Therefore, the microemulsions method is more suitable to synthesize magnetic slurry for the fabrication of magnetic film.