Growth and Characterization of Liquid-Phase Epitaxial Bi-Substituted Iron Garnet Films for Magneto-Optic Application

The effects of the chemical species of host rate-earth ions, melt compositions and growth orientations on the Bi-substitution level and magneto-optic properties of Bi-substituted garnet films grown by liquid-phase epitaxy were examined. For Gd3+ ions, a higher level of Bi substitution was attained than for Y3+ or Lu3+ ions, when garnet films were grown under the same growth conditions. A maximum Faraday rotation coefficient of -2880°/cm at 1.30 µm was observed in the (GdBi)3(FeAlGa)5O12 film with a Bi-substitution level of 1.56 moles per garnet formula unit. The optical absorption coefficient was as small as 1.6 cm-1 in the (GdBi)3(FeAlGa)5O12 film with a Faraday rotation coefficient of -1800°/cm; consequently, a figure of merit of 267°/dB was attained at 1.30 µm.