Studies of the EPR parameters and tetragonal distortion for the Cu2+ center in aluminium oxide

• Published in: Radiation effects and defects in solids Vol. 175; no. 9-10; pp. 952 - 960
• Main Authors: Li, Y. D., Chen, B. J., Yan, C., Zhang, H. M., Xiao, W. B.
• Format: Journal Article
• Language: English
• Published: Abingdon Taylor & Francis 02.09.2020; Taylor & Francis Ltd
• Subjects: Aluminum; Aluminum oxide; Copper; crystal-field theory; defect structure; Distortion; Electron paramagnetic resonance (EPR); Elongated structure; Hyperfine structure; Jahn-Teller effect; Mathematical analysis; Paramagnetic resonance; Parameters; Perturbation methods; Spin-orbit interactions
• ISSN: 1042-0150; 1029-4953
• DOI: 10.1080/10420150.2020.1793340

The electronic paramagnetic resonance (EPR) parameters (g factor g i , and hyperfine structure constants A i , with i = || and ⊥) and tetragonal distortion of the Cu 2+ center in Al 2 O 3 are unified interpreted from the perturbation formulas for a 3d 9 ion in tetragonally elongated octahedral. In the calculations, the impurity Cu 2+ is found to occupy the host trigonally-distorted octahedral Al 3+ site with the tetragonal elongation distortion due to the Jahn-Teller effect, despite the original trigonal distortion of the host cation site. The contributions to EPR parameters from both the spin-orbit coupling of the central ion and that of the ligands are taken into account. The defect structure of the Cu 2+ center (characterized by the relative tetragonal elongation ratio η ≈ 4.3% along the C 4 axis) was determined from the calculation. Furthermore, the calculated results agree well with the experimental data and need fewer adjustable parameters than the previous studies.