Magnetic, Conducting, and Magnetically Conducting Properties of Composite Films (CoFeB+SiO2+N2)

Experimental temperature dependencies of the magnetic moment, specific electrical resistance, and magnetic resistance were obtained for seven composite films (CoFeB+SiO2+N2) with a metallic alloy concentration of x = 0.34-0.51 in the temperature range of 2-400 K and magnetic fields of 0-5 T. The film with x = 0.46 had a finely granulated structure with grain sizes of 20-40 nm. All other films had a mixed structure consisting of granulated and percolation regions. The magnetic moment of all films had values in the range of (0.7-3)·10-6 A·m
²
at T = 300 K. The magnetic moment of the films decreased smoothly with increasing temperature at a rate of 3·10-6 A·m
²
·K⁻
¹
. The specific electrical resistance of the films at T = 300 K varied among different films, ranging from 0.5·10⁻
²
(x = 0.5) to 0.8·10
²
Ohm*m (x = 0.34). The specific electrical resistance of all films decreased smoothly with increasing temperature, indicating that these films exhibit semiconducting conductivity. The film with x = 0.46 exhibited a large magnitude of negative magnetoresistance, reaching 60% at T = 200 K. Films with x = 0.5 and 0.51 had the highest positive magnetoresistance, reaching 20% at T = 250 and 330 K, respectively. The remaining four films showed positive and negative magnetoresistance that did not exceed 5% in the temperature range of 2-400 K.