Spin-Hamiltonian Parameters and Defect Structure of the Copper (2+) Center in Lithium Borate

ABSTRACT

The spin-Hamiltonian parameters (the anisotropic g factors g _|| and g _⊥ and the hyperfine structure constants A _|| and A _⊥) for the impurity Cu²⁺ in Li₂B₄O₇ are theoretically investigated using the high-order perturbation formulas of these parameters for a 3d ⁹ ion in tetragonally elongated octahedra. In the calculation formulas, the tetragonal field parameters D_s and D_t are determined from the superposition model, by considering the relative axial elongation of the oxygen octahedron around Cu²⁺ due to the Jahn-Teller effect. Based on the calculations, the relative axial elongation of about 0.21 Å for the tetragonal Cu²⁺ center was found.

KEYWORDS:

• Cu²⁺
• defect structure
• electron paramagnetic resonance (EPR)
• Li₂B₄O₇

Acknowledgements

This work was supported by the Scientific Research Foundation of the Education Department of Jiangxi Province of China (Grant No. GJJ11469, GJJ11467 and GJJ11129), the National Natural Science Foundation of China (Grant No. 21001056 and 51062004).