The theory of the magnetic properties of rare earth salts: cerium ethyl sulphate

Abstract

The theory of a Ce 3+ ion in a crystal is considered as that of a free ion with a single 4 f electron outside closed shells, and the effect of the surrounding lattice is included as a static crystalline electric field. The problem is solved when this field has C 3k symmetry. It is possible that this theory will be applicable to many cerium salts—it is here applied to the ethyl sulphate for which fairly extensive experimental data are available. It is found that in order to obtain agreement with experiment it is essential to consider small terms of C 3v symmetry, the presence of which is not incompatible with the crystal structure. It is then possible to determine values of the magnitudes of the crystal fields and to fit the magnetic resonance data accurately and the susceptibility data to within a small percentage.