The Faraday effect in TbFe3(BO3)4 and TbAl3(BO3)4 borates

The magnetic field dependences of the Faraday rotation of light and the magnetization of antiferromagnet TbFe3(BO3)4 and paramagnet TbAl3(BO3)4 compounds have been investigated. It is established that the main contribution to the Faraday rotation in the TbFe3(BO3)4 is associated with the Tb3+ subsystem at low temperatures. The antiferromagnetic ordering effects on this contribution is shown.