Theoretical Investigations of the Knight Shifts and the Hyperfine Structure Constants for the Tetragonal Cu2+ Sites in the Bismuth- and Thallium-Based High-Tc Superconductors

The Knight shifts and hyperfine structure constants for the tetragonal Cu2+ sites in bismuth- and thallium-based high-Tc uperconductors ( Bi1:6Pb0:4Sr2Ca2Cu3O10, TlSr2CaCu2O7-y, and Tl2Ba2CuOy) are theoretically investigated from the high-order perturbation formulas of these parameters for a 3d9 ion under tetragonally elongated octahedra in a unified way. The calculation results show good agreement with the observed values. The significant anisotropies of the Knight shifts are attributed to the local tetragonal elongation distortions of the five-(or six-)coordinated Cu2+ sites in these systems. The present studies would be beneficial to establish a complete physical scheme for unified understandings of electron paramagnetic resonance (EPR) and nuclear magnetic resonance (NMR) spectral behaviours of Cu2+ (or other similar 3d9 ions) in the high-Tc superconductors.

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Studies of Knight Shifts and Hyperfine Structure Constants of Tl2Ba2CuO6+y

Defect and Diffusion Forum ◽

10.4028/www.scientific.net/ddf.337-338.49 ◽

2013 ◽

Vol 337-338 ◽

pp. 49-53

Author(s):

Min Quan Kuang ◽

Shao Yi Wu ◽

Xian Fen Hu ◽

Bo Tao Song

Keyword(s):

Hyperfine Structure ◽

Local Structure ◽

High Order ◽

Order Perturbation ◽

Calculation Results ◽

Structure Constants ◽

Knight Shifts ◽

Good Agreement

The Knight shifts and hyperfine structure constants of Tl2Ba2CuO6+yare theoretically studied from the high order perturbation formulas of these quantities for a tetragonally elongated octahedral 3d9cluster. The calculation results reveal good agreement with the observed values. The obvious anisotropies of the Knight shifts can be ascribed to the local tetragonal elongation of the Cu2+site. The results and the local structure of the system are discussed.

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

Zeitschrift für Naturforschung A ◽

10.1515/zna-2020-0326 ◽

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.

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Theoretical Studies on the Gyromagnetic Factors and the Hyperfine Structure Constants for the Tetragonal Copper Center in KTaO3

Zeitschrift für Naturforschung A ◽

10.1515/zna-2005-8-910 ◽

2005 ◽

Vol 60 (8-9) ◽

pp. 615-618 ◽

Cited By ~ 37

Author(s):

Hui-Ning Dong

Keyword(s):

Experimental Data ◽

Electron Paramagnetic Resonance ◽

Hyperfine Structure ◽

Defect Structure ◽

Electrostatic Repulsion ◽

Theoretical Studies ◽

Paramagnetic Resonance ◽

Copper Center ◽

Structure Constants ◽

Electron Paramagnetic

The gyromagnetic factors g∥, g⊥ and the hyperfine structure constants A∥ and A⊥ of the tetragonal Cu2+ center in KTaO3 are theoretically studied in this work. Based on the analyses of the electron paramagnetic resonance results of this center, it is found that the impurity Cu2+ occupies the octahedral Ta5+ site, associated with a nearest-neighbouring oxygen vacancy VO along the C4 axis. Due to the electrostatic repulsion of VO, Cu2+ is displaced away from VO by ΔZ(≈ −0.29 Å ) along the C4 axis. The theoretical values of the g and A factors based on the above defect structure and the impurity displacement agreee reasonably with the experimental data.

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On investigation of high Tc superconductors with Electron Paramagnetic Resonance spectrometers

Physica C Superconductivity ◽

10.1016/j.physc.2010.07.010 ◽

2010 ◽

Vol 470 (21) ◽

pp. 1937-1942 ◽

Cited By ~ 2

Author(s):

D. Shaltiel ◽

H.-A. Krug von Nidda ◽

B.Ya. Shapiro ◽

B. Bogoslavsky ◽

B. Rosenstein ◽

...

Keyword(s):

Electron Paramagnetic Resonance ◽

High Tc Superconductors ◽

Paramagnetic Resonance ◽

High Tc ◽

Electron Paramagnetic

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Investigations of the EPR Parameters and Local Lattice Structure for the Rhombic Cu2+ Centre in TZSH Crystal

Zeitschrift für Naturforschung A ◽

10.1515/zna-2015-0396 ◽

2016 ◽

Vol 71 (3) ◽

pp. 255-260 ◽

Cited By ~ 1

Author(s):

Chao-Ying Li ◽

Shi-Fei Liu ◽

Jin-Xian Fu

Keyword(s):

Lattice Structure ◽

Spin Orbit Coupling ◽

Paramagnetic Resonance ◽

Local Lattice ◽

Ligand Orbital ◽

Epr Parameters ◽

Structure Constants ◽

Electron Paramagnetic ◽

D Orbitals ◽

Good Agreement

AbstractThe electron paramagnetic resonance (EPR) parameters [i.e. g factors gi (i=x, y, z) and hyperfine structure constants Ai] and the local lattice structure for the Cu2+ centre in Tl2Zn(SO4)2·6H2O (TZSH) crystal were theoretically investigated by utilising the perturbation formulae of these parameters for a 3d9 ion under rhombically elongated octahedra. In the calculations, the admixture of d orbitals in the ground state and the ligand orbital and spin-orbit coupling interactions are taken into account based on the cluster approach. The theoretical EPR parameters show good agreement with the observed values, and the Cu2+–H2O bond lengths are obtained as follows: Rx≈1.98 Å, Ry≈2.09 Å, Rz≈2.32 Å. The results are discussed.

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STUDIES OF THE OPTICAL SPECTRA AND EPR PARAMETERS FOR Dy3+ ION IN CaMoO4 CRYSTAL

Modern Physics Letters B ◽

10.1142/s0217984913502096 ◽

2013 ◽

Vol 27 (29) ◽

pp. 1350209

Author(s):

GUO-YA XIE ◽

XIAN-RONG LIU

Keyword(s):

Optical Spectra ◽

Tetragonal Symmetry ◽

Crystal Field Theory ◽

Paramagnetic Resonance ◽

Epr Parameters ◽

Structure Constants ◽

Experimental Values ◽

Yellow Region ◽

Electron Paramagnetic ◽

Good Agreement

CaMoO 4: Dy 3+ used as solid-state laser single crystal, which operate in the yellow region, have important technological applications. In this paper, based on the crystal-field theory, the optical spectra of Dy 3+ in CaMoO 4 crystal are calculated by diagonalizing the 42 × 42 energy matrix. The electron paramagnetic resonance (EPR) parameters g factors g‖ and g⊥ and hyperfine structure constants A‖ and A⊥ of 161 Dy 3+ and 163 Dy 3+ isotopes in CaMoO 4 crystal are investigated using the perturbation formulas of the 4f9 ion in tetragonal symmetry. The needed crystal parameters are determined from the superposition model and the local structure of the studied system. The calculated results are in good agreement with the experimental values.

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Theoretical Studies of the Local Structures and EPR Parameters for the Rhombic Cu2+ Center in Cu0.5Zr2(PO4)3 Phosphate

Zeitschrift für Naturforschung A ◽

10.1515/zna-2015-0128 ◽

2015 ◽

Vol 70 (7) ◽

pp. 553-557

Author(s):

Li Chao-Ying ◽

Huang Ying ◽

Tu Qiu

Keyword(s):

Local Structure ◽

Bond Angle ◽

Theoretical Studies ◽

Paramagnetic Resonance ◽

Local Structures ◽

Epr Parameters ◽

Structure Constants ◽

Electron Paramagnetic ◽

Distortion Angle ◽

Good Agreement

AbstractThe local structure of the rhombic Cu2+ center in Cu0.5Zr2(PO4)3 phosphate is investigated by using the high-order perturbation formulas of electron paramagnetic resonance (EPR) parameters, g-factors gi (i=x, y, z), and hyperfine structure constants Ai for 3d9 ions in rhombically elongated octahedral symmetry. According to the studies, the local axial distortion angle Δα (≈ 5.1°) and the planar bond angle θ (≈ 83.8°) in [CuO6]10- cluster was obtained. The theoretical EPR parameters based on the aforementioned local structure parameters show good agreement with the observed values, and some improvement have been made as compared with the previous studies.

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Electron paramagnetic resonance, electrical resistivity, and magnetization studies in the high Tc superconductors EuBa2Cu3O9−xandEuBa2 (Cu1−yMy)3O9−x (M = Cr, Mn, Fe, Co, Ni, ORZn)

Solid State Communications ◽

10.1016/0038-1098(87)91163-x ◽

1987 ◽

Vol 64 (2) ◽

pp. 241-245 ◽

Cited By ~ 55

Author(s):

S.B. Oseroff ◽

D.C. Vier ◽

J.F. Smyth ◽

C.T. Salling ◽

S. Schultz ◽

...

Keyword(s):

Electron Paramagnetic Resonance ◽

Electrical Resistivity ◽

High Tc Superconductors ◽

Paramagnetic Resonance ◽

High Tc ◽

Electron Paramagnetic

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Theoretical investigations of 63Cu2+ orbital Knight shifts for YBa2Cu4O8

International Journal of Modern Physics B ◽

10.1142/s0217979215420072 ◽

2015 ◽

Vol 29 (25n26) ◽

pp. 1542007 ◽

Cited By ~ 1

Author(s):

Min-Quan Kuang ◽

Shao-Yi Wu ◽

Zhi-Hong Zhang ◽

Xian-Fen Hu

Keyword(s):

Experimental Data ◽

Experimental Verification ◽

High Order ◽

Order Perturbation ◽

Theoretical Investigations ◽

Calculation Results ◽

Knight Shifts ◽

Good Agreement

The temperature-independent orbital Knight shifts for the orthorhombic [Formula: see text] site in [Formula: see text] (Y124) are investigated by utilizing the high order perturbation formulae of these parameters for a [Formula: see text] ion situated into orthorhombically elongated octahedra. The calculation results are in good agreement with the experimental data. The moderate quasi-axial anisotropies of the Knight shifts are ascribed to the elongation distortion of the four-fold coordinated Cu[Formula: see text] site. The [Formula: see text] factors are also theoretically calculated in a uniform way for further experimental verification.

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Investigation Of The Epr Parameters Of An Orthorhombic Cu2+ Center In Cs2zncl4 Crystal

Zeitschrift für Naturforschung A ◽

10.1515/zna-2005-0509 ◽

2005 ◽

Vol 60 (5) ◽

pp. 373-375 ◽

Cited By ~ 3

Author(s):

Hui-Ning Dong ◽

Shao-Yi Wu ◽

Xian-Rong Liu ◽

Wei-Dong Chen

Keyword(s):

Crystal Structure ◽

Electron Paramagnetic Resonance ◽

Hyperfine Structure ◽

Hamiltonian Matrix ◽

Superposition Model ◽

Paramagnetic Resonance ◽

Epr Parameters ◽

Structure Constants ◽

Crystal Field Parameters ◽

Electron Paramagnetic

The electron paramagnetic resonance (EPR) anisotropic g-factors gx, gy and gz and hyperfine structure constants Ax, Ay and Az of Cu2+ in Cs2ZnCl4 crystal are theoretically investigated by the method of diagonalizing the full Hamiltonian matrix. The crystal-field parameters are obtained from the crystal structure by the superposition model. The results, agreeing reasonably with the observed values, are discussed.

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