Ellipsometric Study of Anisotropy Permittivity of Hexagonal Manganites RMnO3 (R = Ho, Tm, Yb)

2012 ◽  
Vol 190 ◽  
pp. 273-276 ◽  
Author(s):  
A.A. Makhnev ◽  
L.V. Nomerovannaya ◽  
Natalia N. Loshkareva ◽  
A.M. Balbashov
Keyword(s):  
Single Crystals ◽  
Absorption Edge ◽  
Near Infrared ◽  
Fundamental Absorption Edge ◽  
Dielectric Tensor ◽  
Broad Absorption ◽  
Intense Band ◽  
Broad Absorption Band ◽  
Ellipsometric Study ◽  
Hexagonal Manganites

The optical properties of single crystals of the hexagonal manganites RMnO3 (R = Ho, Tm, Yb) have been investigated by spectroscopic ellipsometry in the spectral range 0.6-5.0 eV. The measurements show a strong anisotropy of the diagonal elements of the dielectric tensor. It has been demonstrated that the optical absorption edge for the polarization Ec was determined by the intense band of O(2p)Mn (3d) transition centered near 1.6 eV, whereas this band for the polarization Ec was strongly suppressed and shifted toward higher energies by 0.15-0.20 eV. The spectral dependences of the ε1(E) and ε2(E) for HoMnO3, TmMnO3 and YbMnO3 single crystals were qualitatively similar. The broad absorption band at E<1.0 eV clearly appears at the energies below the fundamental absorption edge of all of study compounds. It is possible, the origin of the near-infrared ε2(E) absorption is associated with 4f-4f transitions of R3+ ions.

Optical and Scintillation Properties of Eu-Doped Calcium Orthoborate

2012 ◽  
Vol 508 ◽  
pp. 235-239 ◽  
Author(s):  
Yutaka Fujimoto ◽  
Yoshisuke Futami ◽  
Takayuki Yanagida ◽  
Shunsuke Kurosawa ◽  
N. Kawaguchi ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Absorption Band ◽  
Radio Frequency ◽  
Single Crystals ◽  
Heating System ◽  
Radio Frequency Heating ◽  
Broad Absorption ◽  
Broad Absorption Band ◽  
Decay Times ◽  
Frequency Heating

Single Crystals of Eu-Doped Calcium Orthoborate Have Been Grown by Micro-Pulling (μ-PD) Technique with Radio Frequency Heating System, and its Transmittance, Photoluminescence and Radiation Responses Were Investigated. In Transmittance Spectra, Eu-Doped Crystal Showed Broad Absorption Band around 200-450 nm, which Is due to the Complex of Charge Transfer (CT) Transition and 4f-4f Transition of Eu3+. Intense Eu2+5f-4f and Eu3+4f-4f Emission Peaks Were Observed when Excited to 265 nm and 385 nm, and the Calculated Decay Times Were 230 ns and 1.5 ms, Respectively.241Am 5.5 Mev α-Ray Excited Radioluminescence Spectra Indicated both Eu2+5f-4f and EuSuperscript text3+ 4f-4f Emission Peaks.

scholarly journals Кристаллическая структура и ширина запрещенной зоны твердых растворов (MnIn-=SUB=-2-=/SUB=-S-=SUB=-4-=/SUB=-)-=SUB=-1-x-=/SUB=-·(AgIn-=SUB=-5-=/SUB=-S-=SUB=-8-=/SUB=-)-=SUB=-x-=/SUB=-

2018 ◽  
Vol 52 (8) ◽  
pp. 958
Author(s):  
И.В. Боднарь ◽  
Чан Бинь Тхан
Keyword(s):  
Crystal Structure ◽  
Band Gap ◽  
Single Crystals ◽  
Absorption Edge ◽  
Entire Range ◽  
Spinel Structure ◽  
Cell Parameter ◽  
Fundamental Absorption Edge ◽  
Composition Parameter ◽  
First Time

AbstractThe (MnIn_2S_4)_1– x • (AgIn_5S_8)_ x alloy single crystals are grown for the first time by the Bridgman method in the entire range of component concentrations. The composition of the single crystals and their crystal structure are determined. It is shown that the alloy crystallizes in the cubic spinel structure. The unit-cell parameter of the single crystals ( a ) is calculated, and its dependence on the composition parameter ( x ) is determined. It is established that the parameter a linearly varies with x . From the transmittance spectra in the region of the fundamental absorption edge, the band gap ( E _ g ) of the MnIn_2S_4 and AgIn_5S_8 compounds and (MnIn_2S_4)_1– x • (AgIn_5S_8)_ x alloys is determined, and the dependence of Eg on the parameter x is constructed. It is found that the band gap E _ g nonlinearly varies with x and has a maximum at x = 0.6.

The Fundamental Absorption Edge of Doped CdS Single Crystals

1965 ◽  
Vol 10 (2) ◽  
pp. 525-534 ◽  
Author(s):  
M. S. Brodin ◽  
N. I. Vitrikhovskii ◽  
M. V. Kurik
Keyword(s):  
Single Crystals ◽  
Absorption Edge ◽  
Fundamental Absorption Edge

Fundamental absorption edge in mixed single crystals of II-VI compounds

1988 ◽  
Vol 37 (9) ◽  
pp. 4671-4677 ◽  
Author(s):  
L. Samuel ◽  
Y. Brada ◽  
R. Beserman
Keyword(s):  
Single Crystals ◽  
Absorption Edge ◽  
Fundamental Absorption Edge
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