Temperature and high magnetic field dependence of the Faraday rotation in the terbium iron garnet

The Faraday rotation of terbium iron garnet at 1.15 03BC wavelength is presented. The experimental results have been obtained along the [111] easy direction both in low d.c. field 20 kOe as a function of temperature between 4.2 and 300 K and at room temperature as a function of the applied field (up to 1 200 kOe). The results are analysed in terms of magnetic and electric dipole contributions from the three magnetic sublattices. The Fe3+ contributions are considered to have the same values as in YIG and the total Tb3+ contributions are obtained. The contribution of the magnetic dipole transitions of the R.E. has been calculated when the influence of the crystalline field effect on the Landé factor is taken into account; the electric dipole contribution is found to be strongly temperature and magnetic field dependent. LE JOURNAL DE PHYSIQUE TOME 40, SEPTEMBRE 1979,