Nonlinear field dependence of the Faraday effect in neodymium gallium garnet under high magnetic field

In this paper, we present a theoretical investigation on the Faraday effect in paramagnetic neodymium gallium garnet (Nd3Ga5O12) by taking account of the SO and CF interactions, the superexchange interaction and the external magnetic field. It is demonstrated that under high magnetic field, the Faraday rotation (θ) is strongly nonlinear with the external magnetic field (He) while the coefficients of Hei deeply dependent on the frequency of the incident light and temperature, and the Verdet constant V(θ/He) is also a function of He. Furthermore, theoretical calculations show that the reciprocity of the Faraday effect cannot be neglected under high magnetic field. The theoretical results are in good agreement with the experimental data.