Nanocomposite CO/SiO2 soft magnetic materials

Nanocomposite Co-x/(SiO2)(1-x) soft magnetic materials with Co volume fract ions, x, from 0.4 to 0.9 were synthesized by a wet chemical approach, follo wed by consolidation into toroidal samples. The powder samples consisted of single-domain Co nanoparticles with the fcc structure, coated by thin amor phous SiO2 shells. The measured saturation magnetization was consistent wit h the expected value from the Co volume fraction, indicating the completion of the chemical reaction. The initial complex permeability value obtained from a toroidal sample showed an essentially flat frequency response from 1 0 Hz to 240 MHz, with a quality factor greater than 30. The results show th at the CO/SiO2 nanocomposite system is very promising as a high frequency s oft magnetic material.