On the behavior of Nd3+ in the single crystals of hydrated selenate and sulfate: magnetic measurements and a crystal field investigation

The magnetic measurements on the single crystals of octahydrated neodymium selenate have been carried out in the temperature range 90–300 K. The results are very close to that reported for the isomorphous Nd-sulfate. The observed magnetic moment shows a nearly smooth linear variation with temperature and a least squares fit of the Curie–Weiss law to the observed χ̄ yielded −44.5 K as the paramagnetic Curie temperature. An analysis of the results has been made with a crystal field (CF) of D4 symmetry and an excellent simulation of the observed magnetic behavior of Nd3+ ion in selenate and sulfate was obtained. The CF splitting of the ground and excited multiplets of the ground term and the corresponding eigenfunctions were obtained by the simultaneous diagonalization of the CF and spin orbit interaction matrix in the complete 52-dimensional basis of the 4I term; intermediate coupling was also taken care of to a large extent. The g factors and the anomaly in the electronic heat capacity have been determined. The effect of the proposed CF on the nuclear level splitting and its consequences have been worked out and discussed.