Magneto-optical properties of Sc-substituted dysprosium iron garnet single crystals

Faraday rotation measurements were performed at 1152-nm wavelength in the 6-600 K temperature range under a magnetic field up to 20 kOe applied parallel to the [111], [110], and [100] crystallographic axes of the "as-grown" Dy₃Fe_5-zSc_zO₁₂(z=0.58) (DyIG:Sc) single crystals. A strong anisotropy of both spontaneous and FR susceptibility is observed below 100 K; it is not uniquely tied to the magnetic one. The experimental data are analyzed using the one-ion model. The octahedral scandium substitution affects primarily the N_dc magnetic interactions between the (d) and {c} sublattices as compared to pure DyIG. The temperature variations of electric dipole transitions coefficient of the Dy³⁺ ion are found identical when T>150 K in pure DyIG and in DyIG:Sc.