Magnetic Nanocomposite Cores for Improved High Frequency Magnetic Performance

摘要

Inframat is developing metal/insulator nanocomposites for the next generation of high frequency magnetic applications. Today, all high frequency magnetic components use ferrite cores. Ferrites were developed during World War II and have been used for more than five decades. There is no method available for producing large quantities of soft magnetic materials superior to ferrites at high frequencies (>100 MHz). In ferrite materials, each micro-particle possesses many magnetic domains, causing resonance. Domain wall resonance restricts the frequency characteristics. When the particle size is smaller than the critical size for multidomains, the particle is in a single domain state. Domain wall resonance is avoided, and the material can work at higher frequencies. Our proprietary process involves using an aqueous solution method, resulting in the formation of a thin SiO_2 insulating layer coated on the surface of magnetic nanoparticles. The resulting metal /ceramic nanocomposite cores of Co/SiO_2 has significantly improved high frequency magnetic properties. The material has diminished electric conductivity, resulting in minimal eddy current loss at high frequency up to 1 GHz. By replacing ferrite cores with magnetic nanocomposites, the inductive components could be made lighter, smaller, economical, and highly durable- contributing greatly to improved performance in high frequency devices, e.g., telecommunications.