STUDIES ON THE EPR g FACTORS FOR THE ORTHORHOMBIC NdBa2Cu3O7

2007 ◽  
Vol 21 (24) ◽  
pp. 1627-1633
Author(s):  
SHAO-YI WU ◽  
HUA-MING ZHANG ◽  
ZHI-HONG ZHANG ◽  
LI-HUA WEI
Keyword(s):  
Crystal Field ◽  
Reasonable Agreement ◽  
Structural Data ◽  
Orthorhombic Symmetry ◽  
Superposition Model ◽  
Crystal Field Parameters ◽  
Theoretical Results ◽  
G Factors

The perturbation formulas of the EPR g factors for a 4f3 ion in orthorhombic symmetry are established, by considering the contributions from the admixtures of various states. The formulas are applied to the studies of the g factors for the orthorhombic NdBa 2 Cu 3 O 7. The related crystal-field parameters in the calculations are obtained from the superposition model and the local structural data of the orthorhombic Nd 3+ site in NdBa 2 Cu 3 O 7. The calculated g factors are in reasonable agreement with the observed values. The theoretical results are discussed.

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.

CALCULATION OF EPR PARAMETERSgFACTORS FORCe3+ION INYBa2Cu3O6+xSUPERCONDUCTOR

2005 ◽  
Vol 19 (01n03) ◽  
pp. 143-146 ◽  
Author(s):  
HUI-NING DONG ◽  
HUI-PING DU ◽  
CHANG-KUI DUAN ◽  
XIAO-BING LUO
Keyword(s):  
Angular Momentum ◽  
Crystal Field ◽  
Orbital Angular Momentum ◽  
Second Order ◽  
Order Perturbation ◽  
Orthorhombic Symmetry ◽  
Superposition Model ◽  
Epr Parameters ◽  
Kramers Doublet ◽  
G Factors

The perturbation formulae of EPR parameters g factors gx, gyand gzfor the lowest Kramers doublet of 4f1ion in orthorhombic symmetry are established. In these formulae, the contributions of the covalency effects, the admixture between J=7/2 and J=5/2 states as well as the second-order perturbation (which is not considered in the previous works) via crystal-field and orbital angular momentum interactions are all included. According to these formulae, and by using the superposition model, the g-factors gx, gyand gzfor Ce3+center in YBa2Cu3O6+ xsuperconductor are calculated. The results are discussed.

INVESTIGATIONS ON THE EPR g FACTORS FOR THE SIX-COORDIANTED Cu2+(1) SITE IN YBa2Cu3O6+x

2007 ◽  
Vol 21 (18n19) ◽  
pp. 3250-3253 ◽  
Author(s):  
S. Y. WU ◽  
J. S. YAO ◽  
H. M. ZHANG ◽  
G. D. LU
Keyword(s):  
Structural Data ◽  
Teller Effect ◽  
Tetragonal Crystal ◽  
Jahn Teller ◽  
Jahn Teller Effect ◽  
Crystal Field Parameters ◽  
Tetragonal Crystal Field ◽  
Theoretical Results ◽  
Good Agreement ◽  
G Factors

The EPR g factors g // and g ⊥ for the six-coordinated Cu 2+(1) site in YBa 2 Cu 3 O 6+x are theoretically investigated from the perturbation formulas for a 3 d 9 ion in tetragonally elongated octahedra. The related tetragonal crystal-field parameters Ds and Dt are determined from the superposition model and the structural data for the Cu 2+(1) site, by considering the effective elongation of the oxygen octahedron due to the Jahn-Teller effect of the Cu 2+ cluster. Based on the calculations, the effective elongation (≈ 15%) of the ligand octahedron is obtained for the signals at 100K. As for the EPR signals at room temperature, the elongation declines to merely 4%, corresponding to the smaller anisotropy Δ g (= g // - g ⊥). The theoretical results for the g factors are in good agreement with the observed values, and the local tetragonal distortion due to the Jahn-Teller effect is discussed.

scholarly journals Theoretical Studies On The Gyromagnetic Factors For Nd3+ In Scheelites-Type ABO4 Compounds

2004 ◽  
Vol 59 (12) ◽  
pp. 947-951 ◽  
Author(s):  
Shao-Yi Wu ◽  
Hui-Ning Dong
Keyword(s):  
Crystal Field ◽  
Energy Levels ◽  
Tetragonal Symmetry ◽  
Theoretical Studies ◽  
Superposition Model ◽  
Crystal Field Parameters ◽  
Relationship Of ◽  
Geometrical Relationship ◽  
Theory And Experiment ◽  
G Factors

The gyromagnetic factors for Nd3+ in scheelite-type ABO4 compounds (A = Cd, Ca, Pb, Ba;B = Mo, W) are theoretically studied by the perturbation formulas of the anisotropic g factors g∥ and g⊥ for a 4f3 ion in tetragonal symmetry. In these formulas, the contributions to the g factorsdue to the second-order perturbation terms and the admixtures of various energy levels are takeninto account. The relevant crystal-field parameters are determined by the superposition model andthe local geometrical relationship of the A2+ sites occupied by the impurity Nd3+. The obtained gfactors agree reasonably with the observed values. The discrepancies between theory and experimentare discussed.

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 local structures for Cu2+ centers in M2Zn(SO4)2·6H2O (M = NH4 and Rb) crystals

2021 ◽  
Vol 76 (4) ◽  
pp. 299-304
Author(s):  
Fu Chen ◽  
Jian-Rong Yang ◽  
Zi-Fa Zhou
Keyword(s):  
Crystal Field ◽  
Elongation Ratio ◽  
Paramagnetic Resonance ◽  
Local Structures ◽  
Epr Parameters ◽  
Structure Constants ◽  
Crystal Field Parameters ◽  
Electron Paramagnetic ◽  
Theoretical Results ◽  
Good Agreement

Abstract The electron paramagnetic resonance (EPR) parameters (g factor g i , and hyperfine structure constants A i , with i = x, y, z) and local structures for Cu2+ centers in M2Zn(SO4)2·6H2O (M = NH4 and Rb) are theoretically investigated using the high order perturbation formulas of these EPR parameters for a 3d 9 ion under orthorhombically elongated octahedra. In the calculations, contribution to these EPR parameters due to the admixture of d-orbitals in the ground state wave function of the Cu2+ ion are taken into account based on the cluster approach, and the required crystal-field parameters are estimated from the superposition model which enables correlation of the crystal-field parameters and hence the studied EPR parameters with the local structures of the Cu2+ centers. Based on the calculations, the Cu–H2O bonds are found to suffer the axial elongation ratio δ of about 3 and 2.9% along the z-axis, meanwhile, the planar bond lengths may experience variation ratio τ (≈3.8 and 1%) along x- and y-axis for Cu2+ center in (NH4)2Zn(SO4)2·6H2O and Rb2Zn(SO4)2·6H2O, respectively. The theoretical results show good agreement with the observed values.

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.

STUDIES OF THE LOCAL STRUCTURE AND THE g FACTORS FOR THE ORTHORHOMBICTi3+CENTER IN YAP

2007 ◽  
Vol 21 (12) ◽  
pp. 737-743 ◽  
Author(s):  
JI-ZI LIN ◽  
SHAO-YI WU ◽  
QIANG FU ◽  
HUA-MING ZHANG
Keyword(s):  
Experimental Data ◽  
Local Structure ◽  
Reasonable Agreement ◽  
Orthorhombic Symmetry ◽  
Cluster Approach ◽  
Orthorhombic Distortion ◽  
Large Anisotropy ◽  
G Factors

The local structure and the g factors for the orthorhombic Ti3+center in YAP are theoretically studied from the perturbation formulas of the g factors gx, gyand gzfor a 3d1ion in orthorhombic symmetry based on the cluster approach. The observed large anisotropy of the g factors may be attributed to the significant low-symmetrical (tetragonal and orthorhombic) distortion near the Al3+site occupied by the impurity Ti3+. The calculated g factors in this work show reasonable agreement with the experimental data.

Sign in / Sign up

Export Citation Format

Share Document