Optical and magneto-optical spectra of insulating granular system Co-Al-O

Abstract

Optical and magneto-optical spectra of the insulating granular system Co-Al-O prepared by reactive sputtering are measured in the energy range 0.5-3.8 eV. The trans- verse Kerr effect magnitude in the Co₅₂Al₂₀O₂₈ film attain large values. The data have been interpreted in the frame- work of the effective medium approximations: Bruggeman (BA) and symmetrised Maxwell- Garnett approximation (SMG). The best fit between experimental data and theoretical prediction was obtained in SMG. It is shown that magneto-optical spectra of ferromagnetic composites are highly sensitive to composite microstructure.