Magneto-Optical Properties of (RBi)3Fe5O12 at 0.8 n m Wavelength Band

Optical absorption and Faraday rotation in bulk single crystals of R3-x Bix Fe5 O12 (R=Gd, Tb, Dy, Ho, Y, Er, Tm, Yb, Lu) were measured in the wavelength range from 0.7 to 1.1 ¿m. The peak in the broad absorption band located near 0.9 ¿m shifts to higher energies as the size of the R ions increases, at a rate of ¿0.27 ¿m/Å. Therefore the absorption at a given wavelength near 0.8 ¿m, in the valley between the two broad absorption bands near 0.7 ¿m and 0.9 ¿m, can be minimized by choosing an ion R of the proper size. The magneto-optical figure of merit of Lu2.2Bi0.8Fe5O12 is 13 deg/dB at 0.83 ¿m, and that of Gd2.2Bi0.8Fe5O12 is 24 deg/dB at 0.78 ¿m.