Studies on the spin-Hamiltonian parameters of two Cu2+centers and their defect structures due to Jahn–Teller effect for Cu2+-doped ZnGa2O4spinel

2012 ◽  
Vol 92 (6) ◽  
pp. 760-767 ◽  
Author(s):  
W.C. Zheng ◽  
Y. Mei ◽  
Y.G. Yang ◽  
H.G. Liu
Keyword(s):  
Teller Effect ◽  
Defect Structures ◽  
Spin Hamiltonian ◽  
Jahn Teller ◽  
Jahn Teller Effect ◽  
Hamiltonian Parameters

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.

Investigations of the defect structure for Cu2+ in LaSrGa0.995Cu0.005O4 Ceramics

2015 ◽  
Vol 29 (25n26) ◽  
pp. 1542015 ◽  
Author(s):  
C. C. Ding ◽  
S. Y. Wu ◽  
Y. K. Cheng ◽  
L. J. Zhang
Keyword(s):  
Hyperfine Structure ◽  
Defect Structure ◽  
Teller Effect ◽  
Spin Hamiltonian ◽  
Elongation Ratio ◽  
Jahn Teller ◽  
Jahn Teller Effect ◽  
Structure Constants ◽  
Hamiltonian Parameters ◽  
The Relationship

The defect structure and spin Hamiltonian parameters ([Formula: see text] factors [Formula: see text], [Formula: see text] and the hyperfine structure constants [Formula: see text] and [Formula: see text]) for the tetragonal [Formula: see text] in [Formula: see text] ceramics are theoretically studied from the perturbation formulas of these parameters for a [Formula: see text] ion in a tetragonally elongated octahedron. The impurity [Formula: see text] center exhibits the larger relative tetragonal elongation ratio [Formula: see text] than that [Formula: see text] of the host [Formula: see text] site due to the Jahn–Teller effect. The relationship between the [Formula: see text] anisotropy [Formula: see text] [Formula: see text] and the local tetragonal distortion is analyzed. The present studies would be helpful to the understandings of delocalization of the [Formula: see text] [Formula: see text] orbitals under tetragonal elongation distortion and its role in superconductivity of oxygen cuprates.

THEORETICAL STUDIES OF THE SPIN HAMILTONIAN PARAMETERS AND LOCAL STRUCTURE FOR THE TETRAGONAL Rh2+ CENTER IN RHOMBOHEDRAL BaTiO3

2009 ◽  
Vol 23 (17) ◽  
pp. 2115-2122 ◽  
Author(s):  
HUA-MING ZHANG ◽  
SHAO-YI WU ◽  
XUE-FENG WANG ◽  
YUE-XIA HU
Keyword(s):  
Local Structure ◽  
Relative Elongation ◽  
Experimental Results ◽  
Teller Effect ◽  
Theoretical Studies ◽  
Spin Hamiltonian ◽  
Jahn Teller ◽  
Jahn Teller Effect ◽  
Hamiltonian Parameters ◽  
Good Agreement

The spin Hamiltonian parameters and local structure for the tetragonal Rh 2+ center in rhombohedral BaTiO 3 are theoretically studied from the perturbation formulas of these parameters for a 4d 7 ion with low spin (S=1/2) in tetragonally elongated octahedra. This center is ascribed to substitutional Rh 2+ at the Ti 4+ site in BaTiO 3. The [ RhO 6]10- cluster suffers relative elongation (characterized by the elongation parameter ρ ≈ 0.9%) along the [100] axis due to the Jahn–Teller effect. The tetragonal elongation can entirely depress the slight trigonal distortion of the original Ti 4+ site in rhombohedral BaTiO 3. The calculated spin Hamiltonian parameters based on the above Jahn–Teller elongation show good agreement with the experimental results.

Sign in / Sign up

Export Citation Format

Share Document