Single Crystal Growth and Magneto-Optical Properties of Bi, Al-Substituted Magnetic Garnets

Al was substituted for the iron in the garnet in Bi-substituted magnetic garnet single crystals in an attempt to reduce saturation magnetization and absorption loss. The Bi-, Al-substituted magnetic garnet showed an approximately 20 percent drop in absorption in the neighborhood of 0.8 μm wavelength with no loss in figure of merit because η_F decreased also. Faraday rotation angle measurements established that the saturation magnetism of the Al-substituted crystal was less than half that of the non-substituted crystal. It was also found that as the amount of Bi substituted increases, the compensating temperature (T_comp) decreases, while T_comp increases as the amount of Al substituted is increased. The results showed conclusively that Bi-, Al-substituted garnet is a material with superb magneto-optical properties, with low saturation magnetization and low absorption loss.