Epitaxially grown Bi-substituted iron garnet films for magneto-optic devices

The growth conditions and magnetooptical properties of films of Bi-substituted iron garnets are described. The chemical composition of TmBiFe-Ga garnet films grown from a PbO,B2O3flux has been determined using the radiotracer technique of chemical analysis. The maximum value of the figure of merit (Faraday rotation per unit optical attenuation) found for these films is 2.5 deg/dB at 560 nm. Annealing experiments show that the lead incorporated in these films does not appreciably influence the optical absorption. Using a flux of Bi2O3,MeO2(with Me = Si,Ce), Bi-substituted iron garnet films have been grown. For (TmBiFeGa) garnet films a value of the figure of merit of 3.5 deg/dB at 560 nm is obtained. The Faraday rotation and the optical absorption are measured in the visible for (YBiFeGa)8O12films grown on a large lattice constant substrate. The figure of merit at 560 nm was found to be 4.7 deg/dB.