Magnetic Properties of (Со40Fe40B20)x(SiO2)100 −x Nanocomposites near the Percolation Threshold

The magnetic and magneto-optical properties of (Со40Fe40B20)x(SiO2)100x nanocomposites with x = 30–72 at % are studied. The results reveal the inhomogeneous structure of the nanocomposites, which exhibit both large granules and small particles that make independent contributions of different nature to the magnetic properties of the materials. Specific features of the coercive force near the percolation threshold indicate superferromagnetic ordering in the composites at low temperatures.