Theoretical studies of EPR spectra and defect structure for three Er3+ centers in thorium dioxide

Chai, Rui-Peng; Kuang, Xiao‐Yu; Li, Chenggang; Zhao, Ya-Ru

doi:10.1016/j.cplett.2011.02.013

Cited by 10 publications

(5 citation statements)

References 20 publications

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“…5 as lines, and given in Table 1. The results indicate the high anisotropy of erbium paramagnetic centers and agree with other studies [18][19][20][21].…”

Section: Resultssupporting

confidence: 82%

Growth and EPR properties of ErVO₄ single crystals

et al. 2015

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Abstract. Single crystals of ErVO 4 were grown by the Czochralski method under ambient pressure in a nitrogen atmosphere. Obtained crystals were transparent with strong pink coloring. Electron paramagnetic resonance (EPR) spectra were recorded as a function of the applied magnetic fi eld. Temperature and angular dependences of the EPR spectra of the samples in the 3-300 K temperature range were analyzed applying both Lorentzian--Gauss approximation for diluted medium and Dyson for dense magnetic medium. EPR-NMR program was done to fi nd local symmetry and spin Hamiltonian parameters of erbium ions.

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“…5 as lines, and given in Table 1. The results indicate the high anisotropy of erbium paramagnetic centers and agree with other studies [18][19][20][21].…”

Section: Resultssupporting

confidence: 82%

Growth and EPR properties of ErVO₄ single crystals

et al. 2015

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“…Accordingly, the central RE ions are less affected by the surrounding ligand ions when doped in a certain host, thus resulting in a larger spin-orbit interaction than the crystal field if compared with 3d N transition-metal complexes. [12][13][14][15][16] However, the case may be different for the RE doping from one host to another because of the distinct features between the central ion and the ligand ion, e.g., ionic radius, charge, mass, etc.…”

Section: Introductionmentioning

confidence: 99%

Covalent bonding andJ–Jmixing effects on the EPR parameters of Er^{3 +}ions in GaN crystal

Chai

Liang

et al. 2016

Chinese Phys. B

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The EPR parameters of trivalent Er 3+ ions doped in hexagonal GaN crystal have been studied by diagonalizing the 364×364 complete energy matrices. The results indicate that the resonance ground states may be derived from the Kramers doublet Γ 6 . The EPR g-factors may be ascribed to the stronger covalent bonding and nephelauxetic effects compared with other rare-earth doped complexes, as a result of the mismatch of ionic radii of the impurity Er 3+ ion and the replaced Ga 3+ ion apart from the intrinsic covalency of host GaN. Furthermore, the J-J mixing effects on the EPR parameters from the high-lying manifolds have been evaluated. It is found that the dominant J-J mixing contribution is from the manifold 2 K 15/2 , which accounts for about 2.5%. The next important J-J contribution arises from the crystal-field mixture between the ground state 4 I 15/2 and the first excited state 4 I 13/2 , and is usually less than 0.2%. The contributions from the rest states may be ignored.

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“…For the C 3v (II) centers of Er 3+ ions in CaF 2 and CdF 2 crystals, the lowest Kramers' doublet Γ 7 can be determined by the diagrams by Lea et al [48] and or the method reported in our earlier paper. [49] In the present work, firstly, the optical spectra of Er 3+ ions in CaF 2 and CdF 2 crystals in cubic symmetry are simulated by diagonalizing 364×364 complete energy matrices. [25] The fourthorder and sixth-order intrinsic parameters Ā4 ≈ 76.6 cm −1 , Ā6 ≈ 22.9 cm −1 for CaF 2 :Er 3+ system, and Ā4 ≈ 80.6 cm −1 , Ā6 ≈ 24.3 cm −1 for CdF 2 :Er 3+ system are obtained, respectively, which will be employed in the next studies for the C 3v (II) centers in CaF 2 and CdF 2 .…”

Section: Calculations and Discussionmentioning

confidence: 99%

Determination of charge-compensated C _3υ (II) centers for Er³⁺ ions in CdF₂ and CaF₂ crystals*

Chai¹,

Hao²,

Gao³

et al. 2021

Chinese Phys. B

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A unified theoretical method is established to determine the charge-compensated C 3v (II) centers of Er3+ ions in CdF2 and CaF2 crystals by simulating the electron paramagnetic resonance (EPR) parameters and Stark energy levels. The potential (Er3+–F−– O 4 2 − ) and (Er3+– F 7 − –O2–) structures for the C 3v (II) centers of Er3+ ions in CdF2 and CaF2 crystals are checked by diagonalizing 364 × 364 complete energy matrices in the scheme of superposition model. Our studies indicate that the C 3v (II) centers of Er3+ ions in CdF2 and CaF2 may be ascribed to the local (Er3+–F−– O 4 2 − ) structure, where the upper ligand ion F− undergoes an off-center displacement by ΔZ ≈ 0.3 Å for CdF2 and ΔZ ≈ 0.29 Å for the CaF2 along the C 3 axis. Meanwhile, a local compressed distortion of the ( ErFO 4 ) 6 − cluster is expected to be ΔR ≈ 0.07 Å for CdF2:Er3+ and ΔR ≈ 0.079 Å for CaF2:Er3+. The considerable g-factor anisotropy for Er3+ ions in each of both crystals is explained reasonably by the obtained local parameters. Furthermore, our studies show that a stronger covalent effect exists in the C 3v (II) center for Er3+ in CaF2 or CaF2, which may be due to the stronger electrostatic interaction and closer distance between the central Er3+ ion and ligand O2– with the (Er3+–F−– O 4 2 − ) structure.

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Theoretical studies of EPR spectra and defect structure for three Er3+ centers in thorium dioxide

Cited by 10 publications

References 20 publications

Growth and EPR properties of ErVO₄ single crystals

Growth and EPR properties of ErVO₄ single crystals

Covalent bonding andJ–Jmixing effects on the EPR parameters of Er^{3 +}ions in GaN crystal

Determination of charge-compensated C _3υ (II) centers for Er³⁺ ions in CdF₂ and CaF₂ crystals*

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Theoretical studies of EPR spectra and defect structure for three Er3+ centers in thorium dioxide

Cited by 10 publications

References 20 publications

Growth and EPR properties of ErVO4 single crystals

Growth and EPR properties of ErVO4 single crystals

Covalent bonding andJ–Jmixing effects on the EPR parameters of Er3 +ions in GaN crystal

Determination of charge-compensated C 3υ (II) centers for Er3+ ions in CdF2 and CaF2 crystals*

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Growth and EPR properties of ErVO₄ single crystals

Growth and EPR properties of ErVO₄ single crystals

Covalent bonding andJ–Jmixing effects on the EPR parameters of Er^{3 +}ions in GaN crystal

Determination of charge-compensated C _3υ (II) centers for Er³⁺ ions in CdF₂ and CaF₂ crystals*