Theoretical studies on the spin Hamiltonian parameters of Er~(3+) in Er_xY_(1-x)Ba_2Cu_3O_6

摘要

The spin Hamiltonian (SH) parameters anisotropic g factors g_‖, g_⊥ and the hyperfine structure constants A_‖, A_⊥ of Er~(3+) in Er_xY_(1-x)Ba_2Cu_3O_6 (x = 0.6, 0.2 and 0.05) are theoretically studied from the perturbation formulas of these parameters for a 4f~(11) ion in tetragonal symmetry. In these formulas, the contributions to the SH parameters from the second-order perturbation terms and the admixtures of various excited states are taken into account. The related crystal-field parameters are determined from the superposition model. The theoretical results show reasonable agreement with the observed values.