Soft Magnetic Properties of F Included Films with Metal-Metalloid Systems

stract-Co-Fe-B-F amorphous and nano-crystalline films were prepared using a high deposition rate sputtering apparatus with two opposing targets. The chemical composition of these films could be easily varied from boron-rich/fluorine-poor to boron-poor/fluorine-rich by changing the quantity of fluorine gas. The content of the metalloid (B+F) was found to be constant in amorphous phases. Soft magnetic properties were obtained for films with high B and low F contents. These films had both a high saturated magnetization of 1.6 to 1.8 T, and a high resistivity, from 150 to 1000 μΩ-cm. TEM observations clarified that fluorine decreases the size of mici ocrystals from 10 nm to 5 nm in CoFeBF films with low B contents. The simultaneous occurrence of high B_s and high ρ is attributed to various factors, including the constant metalloid content of (B+F) and a fine texture of mixed phases owing to the presence of F.