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.