Magnetorefractive Effect in (Co 50 Fe 50 ) x (Al 2 O 3 ) 1 - x Granular Films

The reflectivity spectra and the magnetorefractive effect (MRE) of (Co 50 Fe 50 ) x (Al 2 O 3 ) 1 - x metal- dielectric granular films (0.07 < x < 0.52) are analyzed in the IR spectral range λ = 2.5-25 µ m. It is revealed that the specific features observed in the spectra at λ ≈ 8.5 and 20 µ m are associated with the excitation of phonon modes in the dielectric matrix. The magnetorefractive effect in the films is observed below the perco- lation threshold only in p -polarized light and above the percolation threshold for both the p and s polarizations. It is demonstrated that the optical properties of (Co 50 Fe 50 ) x (Al 2 O 3 ) 1 - x films in the IR spectral range, to a first approximation, can be interpreted in the framework of the effective-medium theory and the magnetorefractive effect can be explained in terms of the modified Hagen-Rubens relation. © 2003 MAIK "Nauka/Interperiod- ica".