Preparation and optical properties of single crystal thin films of bismuth substituted iron garnets for magneto-optic applications

Single crystal thin films of Bi substituted iron garnets have been grown by the liquid phase epitaxy technique. The growth conditions and compositions are presented together with the segregation coefficients of Bi and Pb as a function of growth temperature. The Faraday rotation and optical absorption have been measured for wavelengths between 0.7 and 0.46 μm. The superior magneto-optic properties (Faraday rotations of up to ten times larger than that observed for Y₃Fe₅O₁₂) make these epitaxial layers attractive for magneto-optic devices. The influence of Pb incorporation on the optical properties of the films is discussed. Compositions of Bi and Ga(Al) substituted Gd₃Fe₅O₁₂, which exhibit a magnetic compensation temperature near room temperature and high Faraday rotation, have also been prepared. The magnetic switching behaviour as a function of temperature has been determined. It shows that these films are especially suited for thermomagnetic recording using an argon ion laser at a wavelength of 5145 Å.