scholarly journals Crystal-field symmetry and ordered phases in arrays of helicalXYspin chains

1993 ◽  
Vol 47 (5) ◽  
pp. 2661-2670 ◽  
Author(s):  
O. Heinonen
Keyword(s):  
Crystal Field ◽  
Ordered Phases ◽  
Crystal Field Symmetry ◽  
Field Symmetry

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.

Red-emitting enhancement by inducing lower crystal field symmetry of Eu3+ site in CaWO4:Eu3+ phosphor for n-UV w-LEDs

2018 ◽  
Vol 739 ◽  
pp. 439-446 ◽  
Author(s):  
Minfang Xia ◽  
Zhenghua Ju ◽  
Huan Yang ◽  
Zhenbin Wang ◽  
Xiuping Gao ◽  
...  
Keyword(s):  
Crystal Field ◽  
Crystal Field Symmetry ◽  
Field Symmetry

Effect of crystal field symmetry on the shape of the K?1, 2, lines of silicon and some semiconductor compounds

1974 ◽  
Vol 17 (11) ◽  
pp. 1607-1609
Author(s):  
�. P. Domashevskaya ◽  
L. N. Marshakova ◽  
Ya. A. Ugai ◽  
Yu. A. Yurakov
Keyword(s):  
Crystal Field ◽  
Crystal Field Symmetry ◽  
Semiconductor Compounds ◽  
Field Symmetry

Critical properties of a random transverse crystal field Ising model with bond dilution

Open Physics ◽  
2011 ◽  
Vol 9 (4) ◽  
Author(s):  
Ling Wen ◽  
Yan Shi-Lei
Keyword(s):  
Ising Model ◽  
Phase Diagrams ◽  
Crystal Field ◽  
Effective Field ◽  
Square Lattice ◽  
Critical Properties ◽  
Strong Bond ◽  
Ordered Phases ◽  
Bond Dilution ◽  
Global Phase Diagrams

AbstractWithin effective field theory (EFT), the critical properties of a random transverse crystal field Ising model with bond dilution are studied on a square lattice. Under both weak and strong bond dilution conditions, we consider three cases (α = 0,±0.5) of a transverse crystal field ratio, obtaining global phase diagrams in T−D x space for changes in the random transverse crystal field concentration. The phase diagrams obtained for a weak bond dilution are very similar in shape to those of pure bond but with decreases in corresponding ordered phases and critical values. However, the phase diagrams for a strong bond dilution exhibit varieties, including a change in reentrant phenomenon, the occurrence of transverse crystal field degeneration, and the opposite direction crossover of temperature peak value.

Upconversion Luminescence Properties of Er3+ Doped Yb2Ti2O7 Nanophosphor by Gd3+ Codoping

2016 ◽  
Vol 16 (4) ◽  
pp. 3690-3694 ◽  
Author(s):  
B. S Cao ◽  
J. L Wu ◽  
X. H Wang ◽  
Z. Q Feng ◽  
B Dong
Keyword(s):  
Cell Parameter ◽  
Upconversion Luminescence ◽  
Sol Gel ◽  
Nominal Composition ◽  
Face Centered Cubic ◽  
Cubic Crystal ◽  
Crystal Field Symmetry ◽  
Field Symmetry ◽  
Face Centered ◽  
Upconversion Emissions

Er3+ doped Yb2Ti2O7 nanophosphors by Gd3+ codoping with nominal composition of (Er0.05Yb0.95−xGdx)2Ti2O7 (x = 0, 0.2, 0.4, 0.6, 0.8, and 0.95) have been prepared by sol–gel method. −Er3+–Gd3+ codoped Yb2Ti2O7 was characteristic of a typical face-centered cubic crystal phase, and the unit cell parameter increased linearly with the increase of Gd3+ concentration. Under a 976 nm laser diode excitation, both green and red upconversion emissions were observed and the upconversion emissions were enhanced significantly by Gd3+ codoping, showing the strongest green and red emissions at 80 mol% Gd3+ codoping. The intensity ratio of green to red emissions (Igreen/Ired) increased monotonously with the increase of Gd3+ concentration. The energy transfer between Yb3+ and Er3+ and the variation of local crystal field symmetry of Er3+ by the substitution of Yb3+ by Gd3+ ions led to the improvement of upconversion properties of Er3+–Gd3+ codoped Yb2Ti2O7 nanophosphors.

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