Magneto-optic properties of ultrathin bismuth-containing ferrite-garnet films obtained using radio-frequency magnetron sputtering

Magneto-optic properties of ultrathin ferrite-garnet (Bi 2 Dy 1 Fe 4 Ga 1 O 12 ) films with layer thicknesses ranging from 0.6 to 100 nm are studied. The films are produced with the aid of the radio-frequency magnetron sputtering and subsequent high-temperature crystallization annealing. The magnetic circular dichroism is measured in the wavelength interval 300–650 nm. Relatively weak magneto-optic activity in the spectral interval near 360 nm is revealed in the films with nominal thicknesses of 0.6 and 3.7 nm at room temperature but the measured spectrum does not correspond to the spectral dependence of the magnetic circular dichroism of bismuth-containing ferrite-garnets. The spectral dependence of the magnetic circular dichroism that is typical of bismuth-containing ferrite-garnets is observed in the film with a thickness of 10.3 nm and thicker films. The spectra of the magnetic circular dichroism that are typical of nanocrystallites of bismuth-containing ferrite-garnets are obtained in the measurements in the temperature interval 8–200 K.