Study of the Electron Paramagnetic Resonance Parameters for Copper Ions in Lead Titanate Crystal

The electron paramagnetic resonance parameters (g factors g_∥, g_⊥ and hyperfine structure constants A_∥, A_⊥) of PbTiO₃:Cu²⁺ are calculated from the complete diagonalization method and the perturbation theory method. The calculated results obtained by the complete diagonalization method are close to that obtained by the perturbation theory method, and in good agreement with the experimental values. In the complete diagonalization method, the complete diagonalization procedure is established based on the 3d⁹ electron system in tetragonal field. From the calculation of the electron paramagnetic resonance parameters, the local defect structure of the [CuO₆]⁻¹⁰ cluster can be determined as D_4h with R_x = R_y =0.1952 nm, R_z =0.2076 nm.