ACTA PHYSICA POLONICA A SPIN-LATTICE RELAXATION AND SUPERPOSITION MODEL CALCULATION IN Gd3+-DOPED LiErF4 AND LiDyF4 CRYSTALS

The X-band EPR measurements were performed on Gd 3 +-doped LiErF4 and LiDyF4 single crystals at room temperature. The spin-lattice relaxation times were evaluated to be 2.7 x 10 -15 s, 1.0 x 10-15 s and 2.2 x 10' s for LiDyF4 , LiErF4 and LiYbF 4 , respectively. Spin-Hamiltonian parameters are determined and discussed in the light of the superposition model in order to determine the distortion of Gd3 + ion environment in LiREF4 host lattices (RE = Yb, Y, Er, Dy, and Gd)