Dynamic relativistic crystal field contributions to the values of the fourth-order spin-Hamiltonian parameter for Gd3+ in cubic and octahedral coordination

1999 ◽  
Vol 270 (1-2) ◽  
pp. 6-10 ◽  
Author(s):  
W. Pastusiak ◽  
J. Kuriata
Keyword(s):  
Crystal Field ◽  
Fourth Order ◽  
Spin Hamiltonian Parameter ◽  
Octahedral Coordination ◽  
Spin Hamiltonian ◽  
Hamiltonian Parameter

EPR Analysis of Copper Exchanged and Encapsulated Copper (SALEN) Complex in Zeolite - Y

1994 ◽  
Vol 368 ◽  
Author(s):  
N Ulagappan ◽  
V Krishnasamy
Keyword(s):  
Copper Complex ◽  
Zeolite Y ◽  
Spin Hamiltonian Parameter ◽  
Epr Spectra ◽  
Spin Hamiltonian ◽  
Salen Complex ◽  
Hamiltonian Parameter

ABSTRACTCopper exchanged and copper-(salen) complex encapsulated in zeolite-Y were prepared. The encapsulaled complex was analysed by TGA, DRS and IR, which confirms the presence of complex in zeolite. Both copper materials were examined by EPR spectra, and the calculated spin-Hamiltonian parameter indicates the copper complex is more covalent in character than NaCu-Y.

Temperature Dependence of the Crystal-Field Splittings in Gd3+:CaWO4

1971 ◽  
Vol 49 (8) ◽  
pp. 995-1003 ◽  
Author(s):  
J. S. M. Harvey ◽  
H. Kiefte
Keyword(s):  
Electron Spin Resonance ◽  
Low Temperature ◽  
Crystal Field ◽  
Electron Spin ◽  
Fourth Order ◽  
Lattice Vibrations ◽  
Spin Hamiltonian ◽  
Spin Resonance ◽  
Crystal Field Parameters ◽  
Hamiltonian Parameters

The spin-Hamiltonian parameters for Gd3+ in CaWO4 have been measured by the method of electron spin resonance at a number of temperatures between 4.2 °K and 300 °K. The results at 78 °K are in agreement with previous measurements by Hempstead and Bowers.The variations in the crystal-field parameters are interpreted in terms of a limiting low temperature value and a normalized slope at the Debye temperature for each parameter. These quantities are compared with the corresponding quantities for Eu2+ in CaWO4 and, in the case of the fourth-order parameters, for Eu2+ and Gd3+ in cubic CaF2, SrF2, and BaF2. We conclude that the second- and fourth-order splittings each arise from at least three competing mechanisms and that these include a dependence on the amplitude of lattice vibrations. In the case of the trivalent ion, Coulomb forces are also considered to be important.

The magnetic properties of the oxygen–hole aluminum centers in crystalline SiO2. II. [AlO4/H+]+ and [AlO4/Li+]+

1981 ◽  
Vol 59 (11) ◽  
pp. 1709-1718 ◽  
Author(s):  
R. H. D. Nuttall ◽  
J. A. Weil
Keyword(s):  
Magnetic Properties ◽  
Spin Hamiltonian Parameter ◽  
Spin Hamiltonian ◽  
Hole Trapping ◽  
Hamiltonian Parameter ◽  
Oxygen Hole ◽  
Charge Compensator ◽  
X Irradiation ◽  
Hyperfine Splittings ◽  
A Charge

The centers [AlO4/M+]+, formed in α-quartz by X-irradiation at 77 K, contain an aluminum ion substituted for a silicon ion, with an electron removed from a neighboring oxygen by the ionizing radiation. In addition, there is an interstitial ion M+ which acted as a charge compensator before the irradiation. Centers [AlO4/H+]+ and [AlO4/Li+]+ have been re-examined by EPR (at ca. 35 K), including measurement of small hyperfine splittings due to the compensator ions. The spin-Hamiltonian parameter matrices (i.e., [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text]) show that the hole-trapping oxygen in these species is linked via a "short" bond to aluminum (there are two different Si–O bond lengths in quartz). The probable positions of the compensating ions (Li+, H+) in a channel parallel to the crystallographic c-axis are reported.

Defect structure and formation of defect complexes in Cu2+-modified metal oxides derived from a spin-Hamiltonian parameter analysis

2009 ◽  
Vol 107 (19) ◽  
pp. 1981-1986 ◽  
Author(s):  
Rüdiger-A. Eichel ◽  
Michael D. Drahus ◽  
Peter Jakes ◽  
Ebru Erünal ◽  
Emre Erdem ◽  
...  
Keyword(s):  
Metal Oxides ◽  
Defect Structure ◽  
Spin Hamiltonian Parameter ◽  
Parameter Analysis ◽  
Spin Hamiltonian ◽  
Defect Complexes ◽  
Hamiltonian Parameter

scholarly journals EPR of Gd3+ in a Single Crystal of Thorium disulfide (ThS2)

1981 ◽  
Vol 36 (11) ◽  
pp. 1163-1168
Author(s):  
G. Amoretti ◽  
D. C. Giori ◽  
V. Varacca
Keyword(s):  
Single Crystal ◽  
Crystal Field ◽  
Site Symmetry ◽  
Spin Hamiltonian ◽  
Fitting Procedure ◽  
Numerical Fitting ◽  
Crystal Field Symmetry ◽  
Field Symmetry ◽  
Crystal Field Parameters ◽  
Low Symmetry

In this paper we report the experimental angular behaviour of the EPR spectra for a single crystal of Thorium disulfide (ThS2) doped with Gd3+ at very low concentration (of the order of 10 p.p.m.). The experimental data are interpreted in terms of a spin Hamiltonian which reflects the crystal field symmetry at the Th site, that is monoclinic Cs, and therefore shows that the doping ions enter substitutionally without lowering the site symmetry. The low symmetry and the unusually large values of the crystal field parameters b20 and b22 have made it necessary to use a numerical fitting procedure, starting from the exact numerical diagonalization of the energy matrix for any given direction of the static magnetic field.

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