Nuclear magnetic resonance in rare earth metals

McCausland, M A H; Mackenzie, Iain

doi:10.1080/00018737900101385

Cited by 131 publications

(50 citation statements)

References 202 publications

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“…(1) is the electronic Zeeman energy (/.t Bis the Bohr magneton, gj is the Lande factor, J is the total etectronic angular momentum), and the last two temas represent the nuclear hyperfine interactior, of 165Ho. For the free ion, the constant A of the magnetic hyperfine interaction equals 0.812 GHz [7]. The Hamiltonian of the quadrupole hyperfine interaction contains energies of interaction of the nuclear quadrupole moment with the gradient of the crystal electric field and with the intraionic 4f electronic shell, the corresponding coupling constants equal V= -1.1 MHz [8], C--1.764 GHz [7].…”

Section: Single-ion Spectral Parametersmentioning

confidence: 99%

Direct measurements of anticrossings of the electron-nuclear energy levels in LiYF4∶Ho3+ with submillimeter EPR spectroscopy

et al. 2005

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The electron paramagnetic resonance (EPR) spectra of impurity Ho 3+ ions in monocrystals LiYF.~:Ho 3 § (0.1 and 1%) with the natural abundance of 6Li (7.42%) and 7Li (92.58%) isotopes, and in the sample 7LiYF4:Ho3+ (0.1%) isotopically pure in 7Li were taken at the temperature 4.2 K in the frequency range of 165-285 GHz. Resonance transitions between crystal field sublevels (the ground non-Kramers doublet and the nearest excited singlet) of the 518 term were detected. The refined set of crysta] field parameters and the effective constant of the magnetic hyperfine interaction were determined from the detailed analysis of the recorded spectra at frequencies varied by 0.05 GHz. The fine structure of EPR lines with intervals of about 300 MHz observed in the sample LiYF4:Ho 3+ (0.1%) can be interpreted as a result of the isotopic disorder in the Li sublattices. Direct information about energy gaps at the anticrossing points of the electron-nuclear sublevels of the ground doublet was obtained. These gaps are induced by the hyperfine interaction that mixes doublet and singlet states and by random crystal fields. Weak EPR signals from distorted single ion and pair centers of impurity Ho 3+ ions were resolved. From a comparison of the measured and simulated spectra, estimates of spectral parameters of the dimer centers have been obtained.

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Section: Single-ion Spectral Parametersmentioning

confidence: 99%

Direct measurements of anticrossings of the electron-nuclear energy levels in LiYF4∶Ho3+ with submillimeter EPR spectroscopy

et al. 2005

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“…Here A(L, S, J) is the magnetic dipole hyperfine constant (in the free ion A( 3 H 4 ) = 1.093 GHz [14], the corresponding hyperfine constants for other multiplets are obtained using this value and neglecting the core electron polarization contributions which do not exceed 1.5 % of the 4f electron contributions [15]), Q = −5.9 × 10 −30 m 2 [14] is the nuclear quadrupole moment, γ = −70 ± 10 is the Sternheimer antishielding factor [16], α J are reduced matrix elements of the second rank spherical operators, r p are moments of the radial wave function of the 4f electrons calculated in [17], and the electric field gradient at the Pr 3+ nucleus equals…”

Section: Crystal Field Calculationsmentioning

confidence: 99%

High-resolution infrared absorption spectra, crystal-field levels, and relaxation processes inCsCdBr3:Pr3+

et al. 2001

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High resolution low-temperature absorption spectra of 0.2 % Pr 3+ doped CsCdBr3 were measured in the spectral region 2000-7000 cm −1 . Positions and widths of the crystal field levels within the 3 H5, 3 H4, 3 F2, and 3 F3 multiplets of the Pr 3+ main center have been determined. Hyperfine structure of several spectral lines has been found. Crystal field calculations were carried out in the framework of the semiphenomenological exchange charge model (ECM). Parameters of the ECM were determined by fitting to the measured total splittings of the 3 H4 and 3 H6 multiplets and to the observed in this work hyperfine splittings of the crystal field levels. One-and two-phonon relaxation rates were calculated using the phonon Green's functions of the perfect (CsCdBr3) and locally perturbed (impurity dimer centers in CsCdBr3:Pr 3+ ) crystal lattice. Comparison with the measured linewidths confirmed an essential redistribution of the phonon density of states in CsCdBr3 crystals doped with rare-earth ions.

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“…2), we can find the hypenŸ interaction constant Aj = (gj/g)A = 565 MHz in the ground multiplet 7F 6 of Tb 3+ ion with the Lande factor gr = 3/2. This value is close to the hyperfine constant of a free Tb 3+ ion, Ar = 530 MHz[4], and gives a direct evidence that the observed spectrum belongs to terbium centers. By comparing the calculated resonance frequencies v~, [(g~tBB~ + Am)Z + A2]1=) with the measured field dependences vm(Bo) (seeFig.…”

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confidence: 57%

High-frequency EPR of Tb3+-doped KPb2Cl5 crystal

et al. 2004

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High-frequency electron paramagnetic resonance (EPR) spectra of the KPb2CIs:Tb 3+ crystal have been investigated. Three types of spectra were observed in the frequency range of 74-200 GHz. The most intensive spectrum with the resolved hyperiŸ structure corresponded to transitions between sublevels of the mTb3+ ground quasi-doublet with the zero-field splitting (ZFS) close to 48 GHz. Experimental results were analyzed by the exchange charge model of the crystal field affecting terbium ions in low-symmetry Pb 2+ positions with the ehlorine sevenfold eoordination and the charge compensating vacancy in the nearest potassium site. The caleulated values of g-factors and ZFS were in agreement with the experimental data. The nature of a broad EPR line with ZFS of about 180 GHz and of additional weak EPR lines observed as satellites of the main Tb 3+ lines was discussed.

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Nuclear magnetic resonance in rare earth metals

Cited by 131 publications

References 202 publications

Direct measurements of anticrossings of the electron-nuclear energy levels in LiYF4∶Ho3+ with submillimeter EPR spectroscopy

Direct measurements of anticrossings of the electron-nuclear energy levels in LiYF4∶Ho3+ with submillimeter EPR spectroscopy

High-resolution infrared absorption spectra, crystal-field levels, and relaxation processes inCsCdBr3:Pr3+

High-frequency EPR of Tb3+-doped KPb2Cl5 crystal

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