Crystal field investigation of Er3+, Eu3+, and Nd3+ in garnet host lattices

The change of the Stark splitting of the levels of Er3+, Eu3+, and Nd3+ ions in the series of compounds with M3Al5O12 (M = Lu, Yb, Tu, Er, Y, Ho, Dy, Tb) structure is analysed. It is shown that in moving from one garnet to another the twofold parameters of the Hamiltonian of the crystal field (CF) change most strongly. It is found that the regularities of a variation of the CF parameters in the garnet series are the same for the different TR3+ ions, and a change of the crystallographic parameters of the host lattice is responsible for these regularities. It is revealed that the CF symmetry of the TR3+ site in the M3Al5O12 structure deviates from the M3+ cation symmetry. Reasons of the non-monotonous growth of the twofold parameters with the increasing of the lattice constant are discussed.