Magnetic and magneto-optical properties of Ga doped EuIG single crystals

Magnetization and Faraday rotation measurements at 1150 nm have been performed on Eu₃Fe_5-zGa_zO₁₂ single crystals (0⩽z<0.9) quenched at two temperatures, T_q=1200 and 1473 K, as a function of temperature and magnetic field. The heat treatments, which have a greater influence on magnetization than Faraday rotation, shift the magnetic compensation temperature towards lower T when T _q increases. The magnetization results are interpreted on the basis of an induced moment of Eu³⁺ in agreement with W.P. Wolf and J.H. Van Vleck, and G.F. Dionne´s model of ferrimagnetic garnets, assuming that the distribution of Ga on the different sites is the same as YIG:Ga crystals. The contribution of Eu to Faraday rotation in EuIG shows that the gyroelectric magnetooptical coefficient of the model of W.A. Crossley et al., is a linear function of temperature for T>50 K (g_Eu constant)