Crystal field effect on the paramagnetic properties of Dy 3+ ion in dysprosium gallium garnet

Abstract

Magnetization and susceptibility measurements have been performed on single crystals of dysprosium gallium garnet along different axes. The isothermal magnetization curves in the temperature range 1.2K – 4.2K with applied fields up to 70 kOe are well interpreted using a crystal field hamiltonian appropriate for the D 2-symmetry of the rare earth sites. The lowest four levels in the 6H 15 2 manifold calculated with our nine crystal field parameters are in agreement with both the absorption data of Grünberg et al. and the Raman data of Wadsack et al. The calculated g-factors confirm a strong quasi-planar type anisotropy. Between 1.5K and 15K the temperature dependance of the magnetic susceptibility is well account for with our crystal field calculation ; below 5K the Curie-Weiss law was added to take account of magnetic interactions between rare earth ions.