Fabrication of (Co $_{1-{\rm x}}$ Fe $_{\rm x}$ )-B Particles With Magnetic Softness

Amorphous Co_xFe_1-x-B particles with magnetic softness were fabricated by chemical reduction of metal ions. Fabrication conditions to obtain particles with good magnetic softness are described. Co_xFe _1-x-B particles with x= 0.90-0.95 exhibit superb softness because of their nearly zero-magnetostrictive property. The soft properties of the particles are thermally stable compared to other compositions such as Fe-B-P or Co₅₀ Fe₅₀-B. Chains of Co_xFe_1-x-B particles with x=0.95 produced in a magnetic field were studied in detail. The high permeability feature associated with the high aspect ratio of the chain shape exhibits only a slight change after annealing up to 400 degrees. The frequency dispersion of initial permeability exhibits two resonance peaks that are ascribed to the shape anisotropy of the chains.