scholarly journals Theoretical Investigation of the EPR g-factors for Yb3+ in YBa2Cu3O7-δ

2004 ◽  
Vol 59 (6) ◽  
pp. 346-348 ◽  
Author(s):  
Hui-Ning Dong ◽  
Shao-Yi Wu ◽  
Xiao-Bing Luo
Keyword(s):  
Structural Data ◽  
Tetragonal Symmetry ◽  
Superposition Model ◽  
Spin Hamiltonian ◽  
Cluster Approach ◽  
Epr Parameters ◽  
Experimental Values ◽  
Crystal Field Parameters ◽  
Hamiltonian Parameters ◽  
G Factors

The EPR g factors g‖, g⊥ for Yb3+ in YBa2Cu3O7−δ are studied with perturbation formulas based on the cluster approach of the spin-Hamiltonian parameters for a 4f13 ion in tetragonal symmetry. In these formulas, the contributions to the EPR parameters of the covalency effects, the admixture between the J = 7/2 and J = 5/2 states and the second-order perturbation terms are all included. The used crystal-field parameters are calculated with the superposition model and the local structural data of Yb3+ in YBa2Cu3O7−δ . The resulting EPR g factors for Yb3+ ions in the superconductor YBa2Cu3O7−δ agree reasonably with the experimental values. The results are discussed.

Spin-Hamiltonian Parameters of Gd3+ Ion in the Room Temperature Tetragonal Phase of BaTiO3

2014 ◽  
Vol 69 (10-11) ◽  
pp. 606-610 ◽  
Author(s):  
Wei-Qing Yang ◽  
Wen-Chen Zheng
Keyword(s):  
Crystal Field ◽  
Tetragonal Phase ◽  
Structural Data ◽  
Zero Field ◽  
Superposition Model ◽  
Spin Hamiltonian ◽  
Experimental Values ◽  
Crystal Field Parameters ◽  
Hamiltonian Parameters ◽  
Electron Crystal

AbstractThe spin-Hamiltonian parameters (g factors g||, g⊥, and zero-field splittings b02 , b04 , b44 , b06 , b46 ) of the 4f7 Gd3+ ion in the tetragonal phase of a BaTiO3 crystal are calculated through the diagonalization (of energy matrix) method based on the one-electron crystal field mechanism. In the calculations, the crystal field parameters are estimated from the superposition model with the structural data of the studied crystal. It is found that by using three adjustable intrinsic parameters Āk(R0) (k=2, 4, 6) in the superposition model, the seven calculated spin-Hamiltonian parameters are in good agreement with the experimental values, suggesting that the diagonalization method based on one-electron crystal field mechanism is effective in the studies of spin-Hamiltonian parameters for 4f7 ions in crystals.

Studies of the Spin Hamiltonian Parameters and the Local Structure of Tetragonal Zr3+ Centers in Orthophosphate MPO4 (M = Sc, Lu, Y) Crystals

2006 ◽  
Vol 61 (12) ◽  
pp. 688-690 ◽  
Author(s):  
Gui-Qiang Qu ◽  
Wang Fang ◽  
Wen-Chen Zhenga
Keyword(s):  
Lattice Relaxation ◽  
Structural Data ◽  
Tetragonal Symmetry ◽  
Spin Hamiltonian ◽  
Local Lattice ◽  
Structure Constants ◽  
Experimental Values ◽  
Crystal Field Parameters ◽  
Hamiltonian Parameters ◽  
Zircon Type

The spin Hamiltonian parameters (g factors g||, g⊥ and hyperfine structure constants A||, A⊥) of Zr3+ on the tetragonal M3+ (M = Sc, Lu, Y) sites of zircon-type orthophosphate MPO4 crystals are calculated by high-order perturbation formulas of d1 ions in tetragonal symmetry. The crystal-field parameters are estimated by the superposition model and reasonable local structural data of impurity centers. The results show good agreement with the experimental values. It appears that in the case of size mismatch, the explanation of the spin Hamiltonian parameters of a paramagnetic impurity in crystals should take the impurity-induced local lattice relaxation into account.

Investigations of the EPR g Factors for Er3+ in CaMoO4

2004 ◽  
Vol 59 (6) ◽  
pp. 341-345 ◽  
Author(s):  
Shao-Yi Wu ◽  
Hui-Ning Dong
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Crystal Field ◽  
Structural Data ◽  
Order Perturbation ◽  
Tetragonal Symmetry ◽  
Superposition Model ◽  
Paramagnetic Resonance ◽  
Crystal Field Parameters ◽  
Electron Paramagnetic ◽  
G Factors

The electron paramagnetic resonance (EPR) g factors g‖ and g⊥ for Er3+ in CaMoO4 are theoretically investigated by using the perturbation formulas of the g factors for a 4f11 ion in tetragonal symmetry. In these formulas, the contributions to the g factors arising from the second-order perturbation terms and the admixture of various states are considered. The crystal-field parameters for the tetragonally distorted tetrahedra are determined by using the superposition model and the structural data of the impurity Er3+ on the host Ca2+ site in CaMoO4. The calculated g factors agree with the observed values. The validity of the results is discussed.

Theoretical Investigations Of The Spin Hamiltonian Parameters Of Zrsio4:Np4+

2004 ◽  
Vol 59 (7-8) ◽  
pp. 471-475
Author(s):  
Shao-Yi Wu ◽  
Hui-Ning Dong
Keyword(s):  
Experimental Data ◽  
Energy Levels ◽  
Structural Data ◽  
Superposition Model ◽  
Spin Hamiltonian ◽  
Theoretical Investigations ◽  
Structure Constants ◽  
Crystal Field Parameters ◽  
Hamiltonian Parameters ◽  
Theoretical Results

In this work, the spin Hamiltonian (SH) parameters g|| and g⊥, and the hyperfine structure constants A|| and A⊥ for ZrSiO4:Np4+ are investigated on the basis of the perturbation formulas of these parameters for a 5f3 ion in tetragonal (D2d) symmetry. In these formulas, the contributions to the SH parameters from the second-order perturbation terms, the admixtures of various energy levels and the covalency effect are taken into account. The related crystal-field parameters are calculated from the superposition model and the local structural data of the Zr4+ site occupied by the impurity Np4+. The calculated SH parameters agree reasonably with the experimental data. The validity of the theoretical results is discussed.

Theoretical Investigations of the Electron Paramagnetic Resonance g Factors for the Trivalent Cerium Ion in LiYF4 Crystal

2003 ◽  
Vol 58 (9-10) ◽  
pp. 507-510
Author(s):  
Hui-Ning Dong ◽  
Shao-Yi Wu
Keyword(s):  
Tetragonal Symmetry ◽  
Superposition Model ◽  
Paramagnetic Resonance ◽  
Cerium Ion ◽  
Theoretical Investigations ◽  
Epr Parameters ◽  
Crystal Field Parameters ◽  
Electron Paramagnetic ◽  
Perturbation Equations ◽  
G Factors

The perturbation equations of the EPR parameters g‖ and g⊥ for the lowest Kramers doublet of a 4f1 ion in tetragonal symmetry are established. In these equations, the contributions of the covalency effects, the admixture between J = 7/2 and J = 5/2 states and the second-order perturbation (which is not considered previously) are included. The crystal field parameters for the studied Ce3+ center are calculated from the superposition model. Based on the above perturbation equations and related parameters, the EPR g factors for the Ce3+ center in LiYF4 crystals are reasonably explained. The results are discussed.

INVESTIGATIONS OF THE EPR PARAMETERS FORDy3+CENTER INZrSiO4CRYSTAL

2010 ◽  
Vol 24 (03) ◽  
pp. 289-296 ◽  
Author(s):  
HUI-NING DONG ◽  
DENG-FENG LI ◽  
JUN LIU ◽  
DAVID J. KEEBLE
Keyword(s):  
Crystal Field ◽  
Tetragonal Symmetry ◽  
Spin Orbit Coupling ◽  
Spin Hamiltonian ◽  
Field Interaction ◽  
Paramagnetic Resonance ◽  
Epr Parameters ◽  
Structure Constants ◽  
Hamiltonian Parameters ◽  
G Factors

The electronic paramagnetic resonance g factors g‖, g⊥of Dy3+centers and the hyperfine structure constants A‖and A⊥of161Dy3+and163Dy3+isotopes in ZrSiO4crystal are theoretically studied from the perturbation formulas of the spin Hamiltonian parameters for a 4f9ion in tetragonal symmetry. In these formulas, the contributions to g factors due to the J-mixing among the ground6H15/2, the first excited6H13/2and second excited6H11/2states via crystal-field interaction, the admixtures among the states with the same J value via spin-orbit coupling interaction and the interactions between the lowest Kramers doublet Γγ and other 20 Kramers doublets ΓXwithin the states6HJ(J=15/2, 13/2 and 11/2) via crystal-field and orbital angular momentum interactions are considered. The calculated EPR parameters show reasonable agreement with the observed values. The results are discussed.

THEORETICAL INVESTIGATIONS OF THE SPIN HAMILTONIAN PARAMETERS FOR THE TETRAGONALCu2+CENTERS INNH4X(X = Cl, Br, I)

2008 ◽  
Vol 22 (07) ◽  
pp. 843-850 ◽  
Author(s):  
SHAO-YI WU ◽  
XIU-YING GAO ◽  
JI-ZI LIN ◽  
QIANG FU ◽  
HUA-MING ZHANG
Keyword(s):  
Experimental Data ◽  
Reasonable Agreement ◽  
Tetragonal Symmetry ◽  
Superposition Model ◽  
Spin Hamiltonian ◽  
Energy Matrix ◽  
Theoretical Investigations ◽  
Structure Constants ◽  
Crystal Field Parameters ◽  
Hamiltonian Parameters

The spin Hamiltonian (SH) parameters g factors g‖, g⊥and the hyperfine structure constants A‖and A⊥for the tetragonal Cu2+centers (i.e., [ CuX4( H2O )2] clusters) in NH4X ( X = Cl, Br, I ) are theoretically investigated by means of the diagonalization procedure of complete (10×10) energy matrix (DPCEM) for a 3d9ion in tetragonal symmetry. The crystal-field parameters in the energy matrix are determined from the superposition model. The calculated SH parameters are in reasonable agreement with the experimental data.

Investigation of the Spin Hamiltonian Parameters of Yb3+ in CaWO4 Crystal

2004 ◽  
Vol 59 (12) ◽  
pp. 943-946 ◽  
Author(s):  
Hui-Ning Dong ◽  
Shao-Yi Wu
Keyword(s):  
Hyperfine Structure ◽  
Local Structure ◽  
Reasonable Agreement ◽  
Second Order ◽  
Order Perturbation ◽  
Superposition Model ◽  
Spin Hamiltonian ◽  
Structure Constants ◽  
Hamiltonian Parameters ◽  
G Factors

In this paper, the spin Hamiltonian parameters g factors g∥ and g⊥ of Yb3+ and hyperfine structure constants A∥ and A⊥ of 171Yb3+ and 173Yb3+ in CaWO4 crystal are calculated from the two-order perturbation formulae. In these formulae, the contributions of the covalence effects, the admixture between J =7/2 and J =5/2 states as well as the second-order perturbation are included. The needed crystal parameters are obtained from the superposition model and the local structure of the studied system. The calculated results are in reasonable agreement with the observed values. The results are discussed.

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.

The Refined Structure of ThS2 and the Implications on the Superposition Model Analysis of ThS2: Gd3+ Spin Hamiltonian Parameters

1984 ◽  
Vol 39 (8) ◽  
pp. 778-782 ◽  
Author(s):  
G. Amoretti ◽  
G. Calestani ◽  
D. C. Giori
Keyword(s):  
Accurate Determination ◽  
Superposition Model ◽  
Spin Hamiltonian ◽  
Host Crystal ◽  
Intrinsic Parameter ◽  
The Mean ◽  
Crystal Field Parameters ◽  
Hamiltonian Parameters ◽  
Metal Ligand

The crystal structure of ThS2 has been refined starting from single crystal diffractometry data. The accurate determination of the positional parameters allows us to reexamine the SPM analysis of the second degree crystal field parameters for Gd3+ in ThS2 matrix. The fitting of the EPR data is still possible by means of a suitable two exponents power law for the intrinsic parameter only if the substitutional Gd3+ ion displaces in the mirror (bc) plane with respect to the undistorted Th4+ site. The resulting increase of the mean metal-ligand distances agrees with the expected expansion of the ligand cage around the trivalent Gd ion. The applicability of the proposed method to examine the impurity induced distortions in an host crystal is discussed too.

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