Synthesis and spectroscopic studies of Tm3+-doped KY3F10 single crystals

2000 ◽  
Vol 77 (9) ◽  
pp. 693-697 ◽  
Author(s):  
M Diaf ◽  
A Braud ◽  
C Labbé ◽  
J L Doualan ◽  
S Girard ◽  
...  
Keyword(s):  
Low Temperatures ◽  
Room Temperature ◽  
Laser Emission ◽  
Emission Spectra ◽  
Branching Ratios ◽  
Spectroscopic Studies ◽  
Luminescence Decay ◽  
X Ray Diffraction ◽  
X Ray ◽  
First Time

We examine the laser possibilities offered by Tm3+-doped KY3F10. After crystal growth and X-ray diffraction analysis, the optical properties of thulium ions in KY3F10 are determined for the first time. Absorption and emission spectra recorded at low temperatures are used to obtain a set of Stark sublevels, whereas the room-temperature absorption spectra have been allowed to fit the three phenomenological Judd-Ofelt (JO) parameters. The emission line strengths, branching ratios, and radiative lifetimes of levels from 3F4 up to 1D2 are then deduced. A comparison between the calculated lifetimes and the measured luminescence decay curves permits us to check the reliability of the JO analysis for this system. The potential of Tm:KY3F10 for laser emission from 3H4 or 3F4 emitting levels is briefly examined.PACS Nos.: 42.55.Rz, 78.50.Ec, 78.47.+p, 81.10.Fq.

scholarly journals Insertion of Phosphenium Ions into a Bicyclo[1.1.0]Tetraphosphabutane Iron Complex

Molecules ◽  
2021 ◽  
Vol 26 (13) ◽  
pp. 3920
Author(s):  
Martin Weber ◽  
Gábor Balázs ◽  
Alexander V. Virovets ◽  
Eugenia Peresypkina ◽  
Manfred Scheer
Keyword(s):  
Diffraction Analysis ◽  
Room Temperature ◽  
31P Nmr ◽  
Spectroscopic Studies ◽  
Iron Complex ◽  
The Novel ◽  
X Ray Diffraction ◽  
X Ray ◽  
Phosphenium Ions

By reacting [{Cp‴Fe(CO)2}2(µ,η1:1-P4)] (1) with in situ generated phosphenium ions [Ph2P][A] ([A]− = [OTf]− = [O3SCF3]−, [PF6]−), a mixture of two main products of the composition [{Cp‴Fe(CO)2}2(µ,η1:1-P5(C6H5)2)][PF6] (2a and 3a) could be identified by extensive 31P NMR spectroscopic studies at 193 K. Compound 3a was also characterized by X-ray diffraction analysis, showing the rarely observed bicyclo[2.1.0]pentaphosphapentane unit. At room temperature, the novel compound [{Cp‴Fe}(µ,η4:1-P5Ph2){Cp‴(CO)2Fe}][PF6] (4) is formed by decarbonylation. Reacting 1 with in situ generated diphenyl arsenium ions gives short-lived intermediates at 193 K which disproportionate at room temperature into tetraphenyldiarsine and [{Cp‴Fe(CO)2}4(µ4,η1:1:1:1-P8)][OTf]2 (5) containing a tetracyclo[3.3.0.02,7.03,6]octaphosphaoctane ligand.

Magnetic Properties of Sputtered Fe-O and Co-O Thin Films

1995 ◽  
Vol 403 ◽  
Author(s):  
D. V. Dimitrov ◽  
A. S. Murthy ◽  
G. C. Hadjipanayis ◽  
C. P. SWANN
Keyword(s):  
Grain Size ◽  
Low Temperatures ◽  
Room Temperature ◽  
Oxide Films ◽  
X Ray Diffraction ◽  
Dc Magnetron Sputtering ◽  
Large Shift ◽  
X Ray ◽  
Grain Size And Shape ◽  
Spherical Grains

AbstractFe-O and Co-O films were prepared by DC magnetron sputtering in a mixture of Ar and O2 gases. By varying the oxygen to argon ratio, oxide films with stoichiometry FeO, Fe3O4, α-Fe2O3, CoO and Co3O4 were produced. TEM studies showed that the Fe – oxide films were polycrystalline consisting of small almost spherical grains, about 10 nm in size. Co-O films had different microstructure with grain size and shape dependent on the amount of oxygen. X-ray diffraction studies showed that the grains in Fe-O films were randomly oriented in contrast to Co-O films in which a <111> texture was observed. Pure FeO and α-Fe2O3 films were found to be superparamagnetic at room temperature but strongly ferromagnetic at low temperatures in contrast to the antiferromagnetic nature of bulk samples. A very large shift in the hysteresis loop, about 3800 Oe, was observed in field cooled Co-CoO films indicating the presence of a large unidirectional exchange anisotropy.

scholarly journals An operando X-ray diffraction study of chloroaluminate anion-graphite intercalation in aluminum batteries

2018 ◽  
Vol 115 (22) ◽  
pp. 5670-5675 ◽  
Author(s):  
Chun-Jern Pan ◽  
Chunze Yuan ◽  
Guanzhou Zhu ◽  
Qian Zhang ◽  
Chen-Jui Huang ◽  
...  
Keyword(s):  
Low Temperatures ◽  
Room Temperature ◽  
Negative Electrode ◽  
Discharge Voltage ◽  
Battery Life ◽  
X Ray Diffraction ◽  
X Ray ◽  
Stage 4 ◽  
Graphite Intercalation ◽  
Battery Discharge

We investigated rechargeable aluminum (Al) batteries composed of an Al negative electrode, a graphite positive electrode, and an ionic liquid (IL) electrolyte at temperatures down to −40 °C. The reversible battery discharge capacity at low temperatures could be superior to that at room temperature. In situ/operando electrochemical and synchrotron X-ray diffraction experiments combined with theoretical modeling revealed stable AlCl4−/graphite intercalation up to stage 3 at low temperatures, whereas intercalation was reversible up to stage 4 at room temperature (RT). The higher-degree anion/graphite intercalation at low temperatures affords rechargeable Al battery with higher discharge voltage (up to 2.5 V, a record for Al battery) and energy density. A remarkable cycle life of >20,000 cycles at a rate of 6C (10 minutes charge time) was achievable for Al battery operating at low temperatures, corresponding to a >50-year battery life if charged/discharged once daily.

scholarly journals Physical Stability and Viscoelastic Properties of Co-Amorphous Ezetimibe/Simvastatin System

2019 ◽  
Vol 12 (1) ◽  
pp. 40 ◽  
Author(s):  
Justyna Knapik-Kowalczuk ◽  
Krzysztof Chmiel ◽  
Karolina Jurkiewicz ◽  
Natália Correia ◽  
Wiesław Sawicki ◽  
...  
Keyword(s):  
Elevated Temperature ◽  
Viscoelastic Properties ◽  
Room Temperature ◽  
Physical Stability ◽  
Ternary Systems ◽  
Storage Conditions ◽  
X Ray Diffraction ◽  
X Ray ◽  
Temperature Conditions ◽  
First Time

The purpose of this paper is to examine the physical stability as well as viscoelastic properties of the binary amorphous ezetimibe–simvastatin system. According to our knowledge, this is the first time that such an amorphous composition is prepared and investigated. The tendency toward re-crystallization of the amorphous ezetimibe–simvastatin system, at both standard storage and elevated temperature conditions, have been studied by means of X-ray diffraction (XRD). Our investigations have revealed that simvastatin remarkably improves the physical stability of ezetimibe, despite the fact that it works as a plasticizer. Pure amorphous ezetimibe, when stored at room temperature, begins to re-crystallize after 14 days after amorphization. On the other hand, the ezetimibe-simvastatin binary mixture (at the same storage conditions) is physically stable for at least 1 year. However, the devitrification of the binary amorphous composition was observed at elevated temperature conditions (T = 373 K). Therefore, we used a third compound to hinder the re-crystallization. Finally, both the physical stability as well as viscoelastic properties of the ternary systems containing different concentrations of the latter component have been thoroughly investigated.

Temperature dependence of the AV3O7 (A = Ca, Sr) structure

2007 ◽  
Vol 63 (6) ◽  
pp. 836-842 ◽  
Author(s):  
Sebastian Prinz ◽  
Karine M. Sparta ◽  
Georg Roth
Keyword(s):  
Single Crystal ◽  
Temperature Dependence ◽  
Crystal Structures ◽  
Room Temperature ◽  
X Ray Diffraction ◽  
X Ray ◽  
Space Groups ◽  
Temperature Ranges ◽  
First Time

The V4+ (spin ½) oxovanadates AV3O7 (A = Ca, Sr) were synthesized and studied by means of single-crystal X-ray diffraction. The room-temperature structures of both compounds are orthorhombic and their respective space groups are Pnma and Pmmn. The previously assumed structure of SrV3O7 has been revised and the temperature dependence of both crystal structures in the temperature ranges 297–100 K and 315–100 K, respectively, is discussed for the first time.

Direct Interaction of Colloidal Nanostructured ZnO and SnO2 with NO and SO2

2008 ◽  
Vol 8 (12) ◽  
pp. 6389-6397 ◽  
Author(s):  
D. Velasco-Arias ◽  
D. Díaz ◽  
P. Santiago-Jacinto ◽  
G. Rodríguez-Gattorno ◽  
A. Vázquez-Olmos ◽  
...  
Keyword(s):  
Electronic Absorption ◽  
Room Temperature ◽  
Emission Spectra ◽  
Direct Interaction ◽  
X Ray Diffraction ◽  
Wurtzite Phase ◽  
X Ray ◽  
Spontaneous Hydrolysis ◽  
Uv Visible ◽  
Hydrolysis Of

A novel and easy synthesis pathway of small SnO2 nanoparticles is reported. The method consists of the spontaneous hydrolysis of SnCl4·5H2O in dimethyl sulfoxide (DMSO), containing 3% water, at room temperature. The structure of the SnO2 nanocrystals corresponds to that of the cassiterite phase, as shown by powder X-ray diffraction and HR-TEM. The UV-visible electronic absorption and emission spectra of the SnO2 colloids are discussed. The reactions of NO(g) and SO2(g) with ZnO (wurtzite phase) and SnO2 nanocolloids are studied. The interaction of NO with ZnO nanoparticles generates the dissolution of the particles and it is quite probable that NO−13, NO−12, N2O and N2 are formed; while its contact with SO2 probably yields SO−24, SO−23 and also the dissolution of the particles is observed. When these gases are reacted with SnO2, then NO−13, NO−12, SO−23 and SO−24, were respectively obtained.

MBE-Grown GaNAsBi Matched to GaAs with 1.3-μm Emission Wavelength

2004 ◽  
Vol 829 ◽  
Author(s):  
Masahiro Yoshimoto ◽  
Wei Huang ◽  
Kunishige Oe
Keyword(s):  
Room Temperature ◽  
Molecular Beam ◽  
Laser Diodes ◽  
Diffraction Peak ◽  
X Ray Diffraction ◽  
X Ray ◽  
Lattice Matching ◽  
Peak Energy ◽  
First Time ◽  
Lattice Matched

ABSTRACTGaNyAs1-x-yBix alloy lattice-matched to GaAs has been grown by molecular beam epitaxy (MBE). The lattice-matching of GaNyAs1-x-yBix to GaAs was investigated by X-ray diffraction measurements on a series of GaNyAs1-x-yBix with various GaN molar fractions. GaNyAs1-x-yBix lattice-matched to GaAs was obtained, which was confirmed by its diffraction peak overlapped with the peak of GaAs. Photoluminescence (PL) of 1.3 μm was observed from GaNyAs1-x-yBix epilayer matched to GaAs at room temperature. The temperature coefficient of the PL peak energy in a temperature range 150–300K for GaNyAs1-x-yBix was 1/3 of InGaAsP with a bandgap corresponding to 1.3-μm emission. Both lattice-matching to GaAs and bandgap adjustment to 1.3-μm waveband were achieved for GaNyAs1-x-yBix for the first time. This alloy will lead to the fabrication of laser diodes with an emission of temperature insensitive wavelength.

Mineralogy and formation of evaporite deposits from the Lewis Cliff ice tongue, Antarctica

2014 ◽  
Vol 27 (1) ◽  
pp. 73-84 ◽  
Author(s):  
Tingting Liu ◽  
David L. Bish ◽  
Richard A. Socki ◽  
Ralph P. Harvey ◽  
Eric Tonui
Keyword(s):  
Room Temperature ◽  
Precipitation Process ◽  
Secondary Mineral ◽  
X Ray Diffraction ◽  
Sulfate Ions ◽  
X Ray ◽  
Bodies Of Water ◽  
Evaporite Minerals ◽  
Glacial Tills ◽  
First Time

AbstractThe mineralogy of evaporites from the Lewis Cliff ice tongue (LCIT), Antarctica, and their mineral stabilities and transformation behaviours under different temperature and relative humidity (RH) conditions have been evaluated to elucidate formation mechanism(s). A variety of sodium (Na)-rich evaporite minerals were documented using RH-controlled powder X-ray diffraction (XRD) methods including Na-sulfates (mirabilite and thenardite), Na-carbonate/bicarbonates (nahcolite, occasional trona and natron) and Na-borates (qilianshanite and borax). Mirabilite begins to dehydrate to thenardite, and natron to trona and natrite when exposed to room temperature, even when maintained at RH values similar to those measured at the LCIT (50–70%). The boron-mineral qilianshanite was discovered for the first time in Antarctica within the evaporite mounds. The mirabilite-rich mounds are deduced to have formed via a freezing/sublimation process that occurred in glacial or subglacial bodies of water supplied by glacial tills containing microbially oxidized sulfate ions. The needle-like nahcolite crystals growing on the exteriors of the mounds suggest a dissolution/precipitation process involving atmospheric CO2 and water. The co-existence of nahcolite and boron-bearing minerals indicates the presence of a Na+-, HCO3-- and boron-bearing alkaline brine, which produces qilianshanite as a secondary mineral by reaction of nahcolite and borax in atmospheric CO2 and H2O.

scholarly journals Investigation of Y2.1Er0.9(ScxGa1−x)5O12 Matrix Components on the Spectral Properties around 3.0 μm by Micro-Pulling-Down Method

Crystals ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 138
Author(s):  
Zhijiang Che ◽  
Jian Zhang ◽  
Baiyi Wu ◽  
Qiangqiang Hu ◽  
Wenxiang Mu ◽  
...  
Keyword(s):  
Fluorescence Spectra ◽  
Room Temperature ◽  
Lattice Vibration ◽  
Emission Spectra ◽  
X Ray Diffraction ◽  
Mid Infrared ◽  
X Ray ◽  
Electron Probe Microanalyzer ◽  
The Matrix ◽  
Crystal Fibers

Single crystal fibers of 30% Er3+-doped compound of Y3(ScxGa1−x)5O12 have been grown by using the micro-pulling down (μ-PD) technique successfully. Our main purpose is to tune the fluorescence properties by adjusting the ratios of Sc3+ and Ga3+ ions inside the matrix crystals. The crystal structures of the series compounds were measured and analyzed through X-ray diffraction (XRD) measurements. The components and doping elements distributions were measured by the X-ray Fluorescence spectrometry and electron-probe microanalyzer. The absorption and mid-infrared fluorescence spectra, including the fluorescent lifetime of Er3+:4I13/2 and 4I11/2 levels were measured and compared systematically at room temperature. Spectral analysis indicated that the fluorescent lifetime of Er3+:4I13/2 tended to shorten and the emission spectra began to show a red shift when the proportion of YSG increased in the compound. Furthermore, the Raman spectra were measured to reveal the variations of lattice vibration and phonon energy.

Effects on the amorphous Ga2O3 film surfaces by sub-IB-metal-nano-layers

MRS Advances ◽  
2019 ◽  
Vol 4 (5-6) ◽  
pp. 285-292
Author(s):  
L. I. Juárez-Amador ◽  
M. Galván-Arellano ◽  
Y. M. Hernández-Rodríguez ◽  
J. A. Andraca-Adame ◽  
G. Romero-Paredes ◽  
...  
Keyword(s):  
Room Temperature ◽  
Rf Sputtering ◽  
Sem Analysis ◽  
X Ray Diffraction ◽  
Amorphous Films ◽  
X Ray ◽  
Plasmon Frequency ◽  
First Time ◽  
Amorphous Character

AbstractThis work reports by the first time a method to control the geometry of Ga2O3 films nanocrystallites at 350 °C. The formation of controlled shaped nano-crystallites of γ-Ga2O3 from amorphous Ga2O3 films grown by RF-Sputtering at room temperature driven by nano-layers of group IB metals (Cu, Ag or Au) is studied. The reported results can be explained by the role of subsurface metal nano-layers and the non-equilibrium nature of the sputtering processes. To study the effects on the surface structure and their optical properties arrays of amorphous-Ga2O3/IB-metal/amorphous-Ga2O3 were annealed in dry N2 atmosphere at 350 °C by 50, 100 and 150 min. The experimental results can be explained by the evolution of the amorphous character of the films amorphous films towards the nanocrystalline γ-Ga2O3 phase driven by the metal nano-layer seed nature. As the annealing time was increased the transition from amorphous-Ga2O3 to the nanocrystalline γ-Ga2O3 phase was detected by X-ray diffraction analysis. The transition to the nanocrystalline γ-Ga2O3 is demonstrated by the formation of octahedral, triangle and ball shape nanocrystallites with sizes of ∼5 to 50 nm according to FE-SEM analysis. The influence of the metal nano-layer is clearly seen by the shift of the plasmon frequency resonance produced by the Ga2O3/IB-metal/Ga2O3 arrays in the region from 400 to 600 nm caused by the modification of the interface Ga2O3/IB-metal produced by the applied annealing stages.

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