Magneto-optical properties of terbium iron borate.

The Faraday effect induced by an external magnetic field in TbFe3(BO3)4 and TbAl3(BO3)4 borates at a wavelength 633 nm has been investigated. It was found that the terbium subsystem brings the dominant magnetic contribution to the Faraday rotation at low temperatures in borate TbFe3(BO3)4. For both TbFe3(BO3)4 and TbAl3(BO3)4 the magneto-optical coefficients of the terbium subsystem were determined.