Reciprocal and nonreciprocal magnetic linear birefringence in the γ-Dy2S3 sesquisulfide

Abstract

A study has been made of the spectral dependence of the Cotton-Mouton effect (CME) quadratic in magnetic field, nonreciprocal birefringence (NB) linear in magnetic field, and the Faraday effect (FE) in the cubic magnetic semiconductor γ-Dy2S3. Unlike the FE, the CME and the NB in this crystal are anisotropic, with the pattern of the anisotropy being dependent on the photon energy. The dependence of the CME and NB dispersion on the direction of the magnetic field B indicates contribution from a variety of electronic transitions and mechanisms to these phenomena. It is shown that the resonant contributions to the CME and NB in the transparency region originate from electronic transitions near E≅3.4 eV (beyond the band edge Eg=2.8 eV), which are likely transitions from the localized ground state of the Dy3+ ion to states derived from mixing of the band and 4fN−1 5d states of the dysprosium ion. The character of the CME anisotropy in the transparency region and near the local electronic transition 6H15/2 → 6F3/2 connecting states of the unfilled 4f shell of the Dy3+ ion suggests the presence of a strong axial component of the crystal field acting on the rare earth ion.