Visible and Infrared Faraday Rotation and Birefringence of Single-Crystal Rare-Earth Orthoferrites

Faraday rotation and birefringence for propagation parallel to the magnetization, if single-crystal Sm, Eu, Gd, Tb, Dy, Y, Ho, Er, Tm, Yb, and Lu orthoferrite have been measured from 0.6 to 1.8 μ at room temperature. The parameter δ, the relative phase per unit length, and χ, a parameter that relates the strength of the Faraday rotation to the birefringence, have been measured using transmission techniques. From these parameters θ, the intrinsic Faraday rotation, is calculated and found to be nearly the same for all of the orthoferrites except for samarium. In the wavelength region examined the intrinsic Faraday rotation is about three times greater than that in yttrium iron garnet. The optical axis for Eu, Tb, and Yb orthoferrite have been measured at a wavelength of 0.6 μ. The difficulties in using a material with both Faraday rotation and birefringence in devices is discussed.