THEORETICAL EXPLANATIONS OF THE SPIN HAMILTONIAN PARAMETERS FOR Cu²⁺ ION IN LaSrAl_1-xCu_xO₄ SOLID SOLUTION

It is of interest for layered oxides containing copper because they are related to high temperature superconductivity. Among them, LaSrAl_1-xCu_xO₄ solid solution has received much attention due to its elastic and elasto-optic properties and application as promising substrate for high-T_c superconducting thin films. So many theoretical and experimental works have been done to understand the several characteristics of the LaSrAl_1-xCu_xO₄ materials. In this paper, the electron paramagnetic resonance g factors g_//, g_⊥ and hyperfine structure constants A_//, A_⊥ for the tetragonal Cu²⁺ center in LaSrAl_1-xCu_xO₄ solid solution are theoretically explained by the method of diagonalizing the full Hamiltonian matrix. The related crystal field parameters are calculated from the superposition model and the local structural parameters of the impurity Cu²⁺ occupying the host Al³⁺ site. The superposition model parameters used in this work are comparable with those for similar tetragonal (CuO₆)^10- clusters in the previous works. The calculated results are in reasonable agreement with the observed values. The results are discussed.