Representation of energetical and low-field magnetic properties of J = 5/2 rare earth ion states in tegragonal crystal fields

The effect of a tetragonal crystal field on a J = 5/2 rare earth ion is calculated and is presented in a graphical form giving a complete description of the energy, the individual magnetic moment, and Van Vleck susceptibility of each doublet resulting from the crystal field splitting, as a function of two dimensionless parameters and a scale factor. These magnetic properties, which correspond to terms in H and H2 in the development of the energy in presence of a perturbating magnetic field, are given for both the cases, when H is either parallel or orthogonal to the c axis. The results are applied to the compound CeRu2Si2. (author)