Magneto-optical properties of a sputtered Bi-substituted Dy iron garnet-ferrite/spinel-ferrite bilayer

Bi-substituted Dy iron garnet-ferrites, Bi2DyFe4GaO12, were prepared by RF magnetron sputtering on a spinel-ferrite underlayer on a quartz glass subst rate. This study investigated the effect of the spinel underlayer, a mixed crystal of Fe3O4 and gamma-Fe2O3, on improving the magneto-optical properti es. It was found that the presence of the spinel-ferrite underlayer increas ed the Faraday effect, compared to that of a garnet layer with no underlaye r, for which the Faraday effect was almost non-existent. It is concluded th at the high-temperature-treated spinel-ferrite underlayer enhanced the magn eto-optical characteristics. This bilayer structure is therefore promising for magneto-optical recording media. (C) 1999 Elsevier Science B.V. All rig hts reserved.