Investigations of the g factors and crystal field parameters for Ce3+ in CaYAlO4 crystal

Abstract

The EPR g factors g|| and g⊥ for Ce3+ at the tetragonal Y3+/Ca2+ site of CaYAlO4 crystal are calculated from a complete diagonalization (of energy matrix) method. In the method, the contributions to g factors of ground Kramers doublet due to all the rest doublets within the ground and excited multiplets 2F5/2 and 2F7/2 (rather than the doublets within only the ground multiplet 2F5/2 in the previous paper) are considered. The crystal field parameters Bkq in the energy matrix are obtained from the superposition model with the structural data of CaYAlO4 crystal. The calculated g factors are in much better agreement with the experimental values than those from the simple method in the previous paper. The calculated crystal field parameters Bkq are comparable with those of other trivalent rare earth ions in the isomorphous ABCO4 crystals and can be regarded as reasonable. The calculations suggest that the crystal field parameter B20 is positive in Ce3+:CaYAlO4 crystal. The opinion that the parameter B20 must be negative and the simple calculation method of g factors resulting in this opinion are unreliable. It appears that for the reasonable and exact calculations of g factors for 4f1 ion in crystals, the complete diagonalization (of energy matrix) method should be applied.