Theoretical Investigation of Some Magnetic and Spectroscopic Properties of Rare-Earth Ions

Freeman, Arthur J; Watson, R. E.

doi:10.1103/physrev.127.2058

Cited by 1,060 publications

(229 citation statements)

References 85 publications

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“…The hyperfine field in axial symmetry is expressed as : (I and In the following we shall adopt the usual convention to assign a positive sign to HhYp when it is antiparallel to the spin, i. e. parallel to the net magnetization. The free ion value of the Fermi term is --550 kOe [20]. In the case of non axial symmetry, Ganiel [24] has shown that any isolated orbital singlet of the T5 or T3 manifolds produces a quadrupole interaction equal to AE, ; this result has been shown by Zimmermann and Spiering [25] to hold when the spin-orbit coupling is included in the r5 levels (with 1 6 6).…”

Section: C6-441supporting

confidence: 56%

Crystal-Field Effects on High-Spin Ferrous Ion

Varret

1976

J. Phys. Colloques

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RBsumB. -Diverses mkthodes permettent de rksoudre le Hamiltonien klectronique de l'ion ferreux soumis ti un champ cristallin, lorsque seul le terme fondamental 5D de l'ion libre intervient.Nous exposons la methode la plus gknkrale et indiquons quelques effets du champ cristallin sur les interactions hyperfines spontankes ou induites. Nous passons en revue des travaux rkcents ayant pour but de dkterminer le schkma des niveaux de champ cristallin dans des composks variks, et comparons les valeurs obtenues pour les paramares intervenant dans le modble : 1, < r-3 > 3d, AS, AEo. Nous indiquons quelques composks pour lesquels les hypothbes de base : champ cristallin indkpendant du temps et de la tempkrature, relaxation rapide, ne sont pas valides.Abstract. -To treat the electronic Hamiltonian of the ferrous ion in a crystalline field, when only the high spin 5D term is concerned, several methods may be used. We describe the most general one, and indicate some effects of the crystal-field upon the spontaneous or induced hyperfine interactions. We review recent work aiming to determine crystal-field level schemes, and compare the values given for the relevant parameters : 1, < r-3 > 3a, AS, AEo. We also describe a few systems for which the basic assumptions -time and temperature independent crystal field, fas relaxation -are not fulfilled.

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Section: C6-441supporting

confidence: 56%

Crystal-Field Effects on High-Spin Ferrous Ion

Varret

1976

J. Phys. Colloques

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“…We have elected to use the Freeman and Watson values for the average radial integrals (ref. 40), /r k S, and have investigated the effect of these values on the calculated anisotropy direction and also found deviations on the order of 1°when their values are altered nonsystematically by up to 20%. The electrostatic calculations were implemented in a FORTRAN program, MAGELLAN, which is available from the authors upon request.…”

Section: Methodsmentioning

confidence: 99%

An electrostatic model for the determination of magnetic anisotropy in dysprosium complexes

et al. 2013

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Understanding the anisotropic electronic structure of lanthanide complexes is important in areas as diverse as magnetic resonance imaging, luminescent cell labelling and quantum computing. Here we present an intuitive strategy based on a simple electrostatic method, capable of predicting the magnetic anisotropy of dysprosium(III) complexes, even in low symmetry. The strategy relies only on knowing the X-ray structure of the complex and the well-established observation that, in the absence of high symmetry, the ground state of dysprosium(III) is a doublet quantized along the anisotropy axis with an angular momentum quantum number m J ¼ ± 15 / 2 . The magnetic anisotropy axis of 14 low-symmetry monometallic dysprosium(III) complexes computed via high-level ab initio calculations are very well reproduced by our electrostatic model. Furthermore, we show that the magnetic anisotropy is equally well predicted in a selection of low-symmetry polymetallic complexes.

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“…In principle, these parameters can also be calculated from first principles within a point charge model following the procedure outlined in Refs. [41][42][43] The CEF interactions are treated as a perturbation to the spin-orbit coupling and the resulting eigenfunctions of the CEF Hamiltonian are expressed as a linear combination of the |J, m J states within the 2 F 7 2 manifold multiplets.…”

Section: Crystal Field Calculations From First Principles Within Tmentioning

confidence: 99%

Neutron spectroscopic study of crystalline electric field excitations in stoichiometric and lightly stuffedYb2Ti2O7

et al. 2015

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Time-of-flight neutron spectroscopy has been used to determine the crystalline electric field (CEF) Hamiltonian, eigenvalues and eigenvectors appropriate to the J = 7/2 Yb 3+ ion in the candidate quantum spin ice pyrochlore magnet Yb2Ti2O7. The precise ground state (GS) of this exotic, geometrically-frustrated magnet is known to be sensitive to weak disorder associated with the growth of single crystals from the melt. Such materials display weak "stuffing" wherein a small proportion, ≈ 2%, of the non-magnetic Ti 4+ sites are occupied by excess Yb 3+ . We have carried out neutron spectroscopic measurements on a stoichiometric powder sample of Yb2Ti2O7, as well as a crushed single crystal with weak stuffing and an approximate composition of Yb2+xTi2−xO7+y with x = 0.046. All samples display three CEF transitions out of the GS, and the GS doublet itself is identified as primarily composed of mJ = ±1/2, as expected. However,"stuffing" at low temperatures in Yb2+xTi2−xO7+y induces a similar finite CEF lifetime as is induced in stoichiometric Yb2Ti2O7 by elevated temperature. We conclude that an extended strain field exists about each local "stuffed" site, which produces a distribution of random CEF environments in the lightly stuffed Yb2+xTi2−xO7+y, in addition to producing a small fraction of Yb-ions in defective environments with grossly different CEF eigenvalues and eigenvectors.

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Theoretical Investigation of Some Magnetic and Spectroscopic Properties of Rare-Earth Ions

Cited by 1,060 publications

References 85 publications

Crystal-Field Effects on High-Spin Ferrous Ion

Crystal-Field Effects on High-Spin Ferrous Ion

An electrostatic model for the determination of magnetic anisotropy in dysprosium complexes

Neutron spectroscopic study of crystalline electric field excitations in stoichiometric and lightly stuffedYb2Ti2O7

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