Investigations of spin-Hamiltonian parameters and defect structure for Mn4+ in Al2O3 from a two-mechanism model

2008 ◽  
Vol 245 (4) ◽  
pp. 756-760 ◽  
Author(s):  
Xiao-Xuan Wu ◽  
Wen-Lin Feng ◽  
Wang Fang ◽  
Wen-Chen Zheng
Keyword(s):  
Defect Structure ◽  
Spin Hamiltonian ◽  
Mechanism Model ◽  
Hamiltonian Parameters

Investigations of the spin Hamiltonian parameters for VO2+ ions in KZnClSO4 ⋅ 3H2O single crystals

2017 ◽  
Vol 31 (02) ◽  
pp. 1650262
Author(s):  
Chao Tu ◽  
Linhua Xie ◽  
Xiangrong Du
Keyword(s):  
Single Crystals ◽  
Coupling Model ◽  
Spin Hamiltonian ◽  
Third Order ◽  
Ion Clusters ◽  
Mechanism Model ◽  
Double Spin ◽  
State Formula ◽  
High Valence State ◽  
Hamiltonian Parameters

The spin Hamiltonian parameters of VO[Formula: see text] in KZnClSO[Formula: see text]3H2O single crystals are calculated from the third-order perturbation formulas based on the double spin–orbit coupling model for the tetragonal transition-ion clusters in crystals with the ground state [Formula: see text]. In the paper, both the crystal-field (CF) mechanism and the charge-transfer (CT) mechanism (double-mechanism model) are considered to calculate the spin Hamiltonian parameters. The calculated results are in agreement with the experimental data. Moreover, the calculated results show that the CT mechanism cannot be omitted for a high-valence state V[Formula: see text] ions in KZnClSO[Formula: see text]3H2O single crystals. The tetragonal field parameters are also acquired in the paper.

A Study of Spin-Hamiltonian Parameters and Defect Structure for Co2+ Ion in the Tetragonal Zn2+ Site of Ba2ZnF6 Crystal

2010 ◽  
Vol 65 (10) ◽  
pp. 877-881
Author(s):  
Bang-Xing Lia ◽  
Wen-Chen Zheng ◽  
Wei-Qing Yang
Keyword(s):  
Defect Structure ◽  
Reduction Factor ◽  
Teller Effect ◽  
Tetragonal Symmetry ◽  
Spin Hamiltonian ◽  
Effective Spin ◽  
Jahn Teller ◽  
Jahn Teller Effect ◽  
Experimental Values ◽  
Hamiltonian Parameters

The spin-Hamiltonian (SH) parameters (g factors g∥ , g⊥ and hyperfine structure constants A∥, A⊥) for the Co2+ ion in the tetragonal Zn2+ site of a Ba2ZnF6 crystal are calculated from the secondorder perturbation formulas based on the cluster approach for the SH parameters of 3d7 ions in tetragonal symmetry with the effective spin S = 1/2. In the calculations, a reduction factor due to the dynamical Jahn-Teller effect is used. The calculated results are in reasonable agreement with the experimental values, suggesting that the dynamical Jahn-Teller effect should be considered here. The defect structure of the Co2+ center in Ba2ZnF6:Co2+ is also obtained from the calculations. The results are discussed.

Theoretical Investigations of the Defect Structure for Ni3+ in ZnO

2011 ◽  
Vol 318 ◽  
pp. 41-45
Author(s):  
Zhi Hong Zhang ◽  
Shao Yi Wu ◽  
Shan Xiang Zhang
Keyword(s):  
Defect Structure ◽  
Impurity Center ◽  
Spin Hamiltonian ◽  
Theoretical Investigations ◽  
Ligand Orbital ◽  
High Valence State ◽  
Zno Crystal ◽  
Hamiltonian Parameters ◽  
Good Agreement ◽  
The Ideal

The defect structure for Ni3+ in ZnO crystal is theoretically investigated using the perturbation formulas of the spin Hamiltonian parameters for a 3d7 ion in trigonally distorted tetrahedra. In view of the significant covalency of the system due to the high valence state of Ni3+, the ligand orbital and spin-orbit coupling contributions are taken into account in a uniform way based on the cluster approach. The impurity Ni3+ is found not to occupy the ideal Zn2+ site in ZnO but to undergo the small axial displacement of about 0.044 Ǻ away from the oxygen triangle along the C3 axis. The theoretical spin Hamiltonian parameters based on the above impurity displacement show good agreement with the experimental data. The defect structure of this impurity center is compared with that for the similar Fe3+ in ZnO.

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