Calculations of the Paramagnetic Susceptibilities for LiYF4:Nd3+ and LiYF4:Er3+ from the Crystal Field Effects

LiYF₄ crystal doped with rare earth ions has numerous optical applications due its properties like a wide range transparency, low value of induced nonlinear refractive index, optical and thermal stability. The energy levels and wave functions of Nd³⁺ and Er³⁺ ions doped in LiYF₄ host has been obtained by diagonalizing the corresponding crystal field Hamiltonian. They are used to compute the temperature dependence and anisotropy of the molar paramagnetic susceptibility. From the results of calculations, the Curie constants and Jahn-Teller stabilization energy for both ions in LiYF₄ are evaluated. Comparison with experiment shows that the results are quite satisfactory.