Features of optical anisotropy of europium and terbium iron garnets

•We offer model-based theory of magneto-optical anisotropy of Tb3Fe5O12 and Eu3Fe5O12.•A theory explains the experimentally observed nonreciprocity of MLB spectra.•The possibility of anomalous anisotropy is demonstrated in these cubic crystals.

The results of investigation of magnetic linear birefringence (MLB) and magnetic linear dichroism of Tb3Fe5O12 (TbIG) iron garnet (IG) on 7F67F6–7F07F0 and 7F67F6–7F17F1 optical transitions and Eu3Fe5O12 (EuIG) iron garnet on 7F07F0–7F67F6 at the variation of the directions of the magnetization vector I relative to the electric vector E linearly polarized light that propagates through single crystal iron garnets are presented. The measurements were made on Tb3Fe5О12 and Eu3Fe5O12 single-crystal samples in the form of plates 100 μm thick cut in the (1 1 0) and (1 0 0) plane a temperature of T = 82 K and in a magnetic field H = 22 kOe. The absorption spectra of the linearly polarized light were studied. It is shown that MLB and dichroism in the region of the 7F67F6–7F07F0 and 7F07F0–7F67F6 absorption bands reach values 10−3. The nonreciprocity of MLB spectra and dichroism with the change of the relative orientation of the magnetization vector I and the light wave vector is first experimentally discovered. This effect may be used as a base for the design of the different transducers such as a magnetooptical optical channels commutator.