998 resultados para DY-3
Resumo:
BaF_2LnAlO_3(Ln=La,Gd,Y),LnAlO_3Ce~(3+),Tb~(3+),Dy~(3+)Ce-Tb,Ce-Dy,Ln,LnAlO_3,,
Resumo:
Dy~(3+),Sm~(3+)Ce~(3+)M_3La_2(BO_3)_4(M=Ca,Sr,Ba);Dy~(3+);Sm~(3+)Sm~(3+)Eu~(3+)4fDy~(3+),Sm~(3+)Ce~(3+)
Resumo:
The persistent luminescence materials, barium aluminates doped with Eu(2+) and Dy(3+) (BaAl(2)O(4): Eu(2+),Dy(3+)), were prepared with the combustion synthesis at temperatures between 400 and 600 degrees C as well as with the solid state reaction at 1500 degrees C. The concentrations of Eu(2+)/Dy(3+) (in mol% of the Ba amount) ranged from 0.1/0.1 to 1.0/3.0. The electronic and defect energy level structures were studied with thermoluminescence (TL) and synchrotron radiation (SR) spectroscopies: UV-VUV excitation and emission, as well as with X-ray absorption near-edge structure (XANES) methods. Theoretical calculations using the density functional theory (DFT) were carried out in order to compare with the experimental data. (C) 2010 Elsevier Inc. All rights reserved.
Resumo:
Polycrystalline Eu(2+) and Dy(3+) doped barium aluminate materials, BaAl(2)O(4):Eu(2+),Dy(3+), were prepared with solid state reactions at temperatures between 700 and 1500 degrees C. The influence of the thermal treatments on the stability, homogeneity and structure as well as to the UV-excited and persistent luminescence of the materials was investigated by X-ray powder diffraction, SEM imaging and infrared spectroscopies as well as by steady state luminescence spectroscopy and persistent luminescence decay curves, respectively. The IR spectra of the materials prepared at 250, 700, and 1500 degrees C follow the formation of BaAl(2)O(4) composition whereas the X-ray powder diffraction of compounds revealed how the hexagonal structure was obtained. The morphology of the materials at high temperatures indicated important aggregation due to sintering. The luminescence decay of the quite narrow Eu(2+) band at ca. 500 nm shows the presence of persistent luminescence after UV irradiation. The dopant (Eu(2+)) and co-clopant (Dy(3+)) concentrations affect the crystallinity and luminescence properties of the materials. (C) 2009 Elsevier B.V. All rights reserved.
Resumo:
MoSb_2O_5R_2O_3R'_2O_3Bi_2O_3Bi~(3+)ThorntonBa_2BiSbO_6Ba_2GdSbO_6EECEHKOM_2RSbO_6 (M = BaSrCa, R = La Y)M_2RSbO_6Sm~(3+)Eu~(3+)Dy~(3+)Ho~(3+)Er~(3+)Tm~(3+)Bi~(3+)Bi~(3+)X-M_2RSbO_6(M = BaSrR = LaYGdBi)Fm3mOhCa_2YSbO_6P_(21)M_2RSbO_6 (M = BaSrCa; R = GdYBi)Ba_2GdSbO_6Sb_2O_5M_2RSbO_6Sb_2O_3520 Sb_2O_5Eu~(3+)Ba_2YSbO_6:Eu~(3+)Br_2YSbO_6:Eu~(3+), Bi~(3+)254nmEu~(3+)595nmBi~(3+)325nmBi~(3+)Eu~(3+)Eu~(3+)595nmBi~(3+)Eu~(3+)Bi~(3+)~1S 3P_1Eu~(3+)~5D_0~5D_0 7F_1Eu~(3+)Sr_2YSbO_6:Eu~(3+)Sr_2YSbO_6:Eu~(3+), Bi~(3+)245nmEu~(3+)595nmBi~(3+)335nmBi~(3+)Eu~(3+)Ba_2YSbO_6:Eu~(3+)Ba_2YSbO_6:Eu~(3+), Bi~(3+)Eu~(3+)Ca_2YSbO_6:Eu~(3+)Ca_2YSbO_6:Eu~(3+), Bi~(3+)396nmEu~(3+)613nmBi~(3+)313nmBi~(3+)Eu~(3+)Bi~(3+)3P_1 ~1S_0400nmEu~(3+)~7F_0 ~5L_6396nm~5L_6~5D_0~7F_2Ca_2Y_(0.96)Eu_(0.04)SbO_6Eu~(3+)Eu~(3+)Fm3m Ba_2YSbO_6Sr_2YSbO_6Oh~5D_0 ~7F_1Eu~(3+)P_(21)~5D_0 ~7F_2M_2YSbO_6:R~(13+)(M = BaCa; R' = SmDyHoErTm)Sm~(3+)Dy~(3+)Ho~(3+)Bi~(3+)Ca_2YSbO_6:Bi~(3+)Bi~(3+)240nm~1S_0 ~1P_1315nm~1S_0 ~3P_1400nm~3P_1 ~1S_0
Resumo:
Eu~(3+),Dy~(3+)Bi~(3+)LaMSb_2O_7(M=Li,Na,K),LaNaSb_2O_7:Dy~(3+)Eu~(3+)Dy~(3+)281nm,Bi~(3+)Eu~(3+)
Resumo:
Operation of a single-clad Dy 3+-doped ZrF 4-BaF 2-LaF 3-AlF 3-NaF (ZBLAN) fiber laser operating at mid-infrared near 3 m is presented. The laser is pumped by an Yb 3+-doped silica fiber laser centered at 1088 nm. An output of near 0.1 W with a slope efficiency of up to 23% with respect to absorbed pump power was measured. The laser performance, theoretical modeling and laser spectrum of Dy fiber laser system with respect to various cavity losses are studied. The experimental slope efficiency is more than 4.5 times higher than the previous demonstration, and is 64% of the Stokes efficiency limit. The efficiency was improved by using cavity mirrors of reflectivities of 99 and 50%. The emission central wavelength and spectral width are found to be dependent on the pump power and output coupler, reflectivity. 2011 by Astro Ltd., published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA.
Phase transitions and rare-earth magnetism in hexagonal and orthorhombic $DyMnO_{3}$ single crystals
Resumo:
The floating-zone method with different growth ambiences has been used to selectively obtain hexagonal or orthorhombic DyMnO3 single crystals. The crystals were characterized by x-ray powder diffraction of ground specimens and a structure refinement as well as electron diffraction. We report magnetic susceptibility, magnetization and specific heat studies of this multiferroic compound in both the hexagonal and the orthorhombic structure. The hexagonal DyMnO3 shows magnetic ordering of Mn3+ (S = 2) spins on a triangular Mn lattice at T-N(Mn) = 57 K characterized by a cusp in the specific heat. This transition is not apparent in the magnetic susceptibility due to the frustration on the Mn triangular lattice and the dominating paramagnetic susceptibility of the Dy3+ (S = 9/2) spins. At T-N(Dy) = 3 K, a partial antiferromagnetic order of Dy moments has been observed. In comparison, the magnetic data for orthorhombic DyMnO3 display three transitions. The data broadly agree with results from earlier neutron diffraction experiments, which allows for the following assignment: a transition from an incommensurate antiferromagnetic ordering of Mn3+ spins at T-N(Mn) = 39 K, a lock-in transition at Tlock-in = 16 K and a second antiferromagnetic transition at T-N(Dy) = 5 K due to the ordering of Dy moments. Both the hexagonal and the orthorhombic crystals show magnetic anisotropy and complex magnetic properties due to 4f-4f and 4f-3d couplings.
Resumo:
The floating-zone method with different growth ambiences has been used to selectively obtain hexagonal or orthorhombic DyMnO3 single crystals. The crystals were characterized by x-ray powder diffraction of ground specimens and a structure refinement as well as electron diffraction. We report magnetic susceptibility, magnetization and specific heat studies of this multiferroic compound in both the hexagonal and the orthorhombic structure. The hexagonal DyMnO3 shows magnetic ordering of Mn3+ (S = 2) spins on a triangular Mn lattice at T-N(Mn) = 57 K characterized by a cusp in the specific heat. This transition is not apparent in the magnetic susceptibility due to the frustration on the Mn triangular lattice and the dominating paramagnetic susceptibility of the Dy3+ (S = 9/2) spins. At T-N(Dy) = 3 K, a partial antiferromagnetic order of Dy moments has been observed. In comparison, the magnetic data for orthorhombic DyMnO3 display three transitions. The data broadly agree with results from earlier neutron diffraction experiments, which allows for the following assignment: a transition from an incommensurate antiferromagnetic ordering of Mn3+ spins at T-N(Mn) = 39 K, a lock-in transition at Tlock-in = 16 K and a second antiferromagnetic transition at T-N(Dy) = 5 K due to the ordering of Dy moments. Both the hexagonal and the orthorhombic crystals show magnetic anisotropy and complex magnetic properties due to 4f-4f and 4f-3d couplings.
Resumo:
N_2-H_2M_2~ICO_3 + M_3~(II)(PO_4)_2 + M_2~(III)O_3 + (NH_4)_2HPO_4 + M~(II)F_2 M_x~IM_(10-2x)~(II)M_x~(III)(PO_4)_6F_2 + NH_3 + H_2OM~I = Li~+, Na~+, K~+; M~(II) = Ca~(2+), Sr~(2+); M~(III) = Y~(3+), La~(3+), Gd~(3+); X = 0.5, 1, 2, 3XEu~(3+)M_(10)~(II)(PO_4)_6F_2(Pb_3/m)ac9.416.89 AM~I, M~(II)M~(III)XCe~(3+)Na_2Ca_6La_2(PO_4)_6F_2Ce~(3+)Ce~(3+)-Mn~(2+), Ce~(3+)-Re~(3+) (Re~(3+) = Pr~(3+)Nd~(3+)Sm~(3+)Tb~(3+)Dy~(3+)Tm~(3+)Ho~(3+)Er~(3+))Ce~(3+)-Mn~(2+)-Re~(3+) (Re~(3+) = Dy~(3+), Nd~(3+))Na_2Ca_6La_2(PO_4)_6F_2:Ce~(3+)338358nm~2D-~2F_(5/2)~2D-~2F_(1/2)~2D-~2F_(6/2)~2D-~2F_(7/2)Ce~(3+)F~-Ce~(3+)-Ce~(3+)Ce~(3+)Mn~(2+)Ce~(3+)Re~(3+)A. Ce~(3+)-Sm~(3+)Tb~(3+)Dy~(3+)Tm~(3+)BCe~(3+)-Nd~(3+)Pr~(3+)C. Ce~(3+)-Ho~(3+), Er~(3+)ABCe~(3+)(_T)_A > (_T)_BCe~(3+)-Ho~(3+)Ce~(3+)-Er~(3+)Ho~(3+)Er~(3+)Ce~(3+)Ce~(3+)-Mn~(2+)-Re~(3+)Ce~(3+)Mn~(2+)Re~(3+)Ce~(3+)-Mn~(2+)-Re~(3+)Ce~(3+)-Mn~(2+)Ce~(3+)-Re~(3+)Ce~(3+)-Mn~(2+)-Re~(3+)M. YokataCe~(3+)Ce~(3+)-Mn~(2+)Ce~(3+)-ReCe~(3+)-Mn~(2+))-Re~(3+)Ce~(3+)Ce~(3+)Ce~(3+)(_f, _R)
Resumo:
Reaction of anhydrous lanthanide trichlorides with tetrahydrofurfuryl indenyl lithium in THF afforded bis(tetrahydrofurfurylindenyl) lanthanocene chlorides complexes (C4H7OCH2C9H6)(2) LnCl, Ln = Nd (1), Sm (2), Dy (3), Ho (4), Er (5), Yb (6). The X-ray crystallographic structures of all the six complexes were determined and these indicate that they are unsolvated nine-coordinate monomeric complexes with a trans arrangement of both the sidearm and indenyl rings in the solid state. They belong to the same crystal system (orthorhombic) and space group (P2(1)2(1)2(1)) with the same structure. Especially, they are more stable to air and moisture than the corresponding unsubstituted indenyl lanthanide complexes.
Resumo:
MgAl(2)O(4):Eu, Dy nanoparticles were prepared by citrate sol-gel method and thermally treated at 600, 700, 800 and 900 degrees C. The trivalent europium ion is partially reduced to the divalent state at 700 and 800 degrees C. Infrared spectra of the phosphors showed bands around 700 and 520 cm(-1) corresponding to the AlO(6) groups. X-ray diffraction patterns present sharp reflections of samples heated from 700 to 900 degrees C indicating the MgAl(2)O(4) spinel phase. Grain size in the range 20-30 nm were observed by measurement of transmission electron microscopy (TEM). The emission spectra of the phosphors show a broadened band at 480 nm assigned to the 4f(G)5d -> 4f(7) ((8)S(7/2)) transition of Eu(2+) ion overlapped to the (4)F(9/2) -> (6)H(15/2) transition of the Dy(3+) ion. Besides, the (4)F(9/2) -> (6)H(13/2) transition (579 nm) of Dy(3+) ion is overlapped with the (5)D(0) -> (7)F(0) (578 nm) and (5)D(0) -> (7)F(1) (595 nm) transitions from the Eu(3+) ion. Excitation spectra of the sample heated at 900 degrees C monitoring the excitation at 615 nm of (5)D(0) -> (7)F(2) transition of Eu(3+) ion exhibit a broad band assigned to the O -> Eu(3+) ligand-to-metal charge-transfer states (LMCT) around 280 nm. The samples present green persistent luminescence after exposure to UV radiation. The chromaticity coordinates were obtained from the luminescence emission spectrum. (C) 2008 Elsevier B.V. All rights reserved.
Resumo:
Employing nitronyl nitroxide lanthanide(III) complexes as metallo-ligands allowed the efficient and highly selective preparation of three series of unprecedented heterotri-spin (Cu Ln-radical) one-dimensional compounds. These 2p-3d-4f spin systems, namely Ln(3)Cu(hfac)II(NitPhOAII)41 (Ln(III)=Gd 1(Gd), Tb 1(Tb), Dy 1(Dy); NitPhOAII=2-(4'-allyloxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3- oxide), Ln(3)Cu(hfac)II(NitPhOPO4] (1-nrn=Gd 2Gd, Tb 2Tb, Dy 2(Dy), Ho 2HOf Yb 2yb; NitPhOPr= 2-(4'-propoxyphenyI)-4,4,5,5-tetramethyl-imidazoline-1-oxyl-3-oxide) and Ln3Cu(hfac)II(NitPhOB441 (LnIm=Gd 3Gd, Tb 3Tb, Dy 3(Dy); NitPhOBz=2-(4'-benzyloxy- phenyl)-4,4,5,5-tetramethyl-imidazoline-1-oxyl-3-oxide) involve O-bound nitronyl nitroxide radicals as bridging ligands in chain structures with a Cu-Nit-Ln-Nit-Ln-Nit-Ln-Nit] repeating unit. The dc magnetic studies show that ferromagnetic metal radical interactions take place in these heterotri-spin chain complexes, these and the next-neighbor interactions have been quantified for the Gd derivatives. Complexes 1Tb and 2Tb exhibit frequency dependence of ac magnetic susceptibilities, indicating single-chain magnet behavior.
Resumo:
Cathaya argyrophyllaRAPD82DNA 1. 10181586DNA8s0.0022s0.0027DYs0.0026s0.0027BMs0.0014s0.0018DLYCAMOVA20.059.37FSTFST0.294FST =0.131-0.319Nm=1.2 2 2nad1nad4200923DLBMYCDY3GST=1.044200912847NST (0.138)GST (0.134)2009mismatch distribution 3. 2009cad64200960cad2TTC80DYYC71693.395.2%91.3% 4 44DL(BM)(YC)(DY) 4
Resumo:
A novel heavy-metal chalcogenide glass doped with a high dysprosium ion (Dy(3+)) concentration was prepared by the well-established melt-quenching technique from high-purity elements. The results show that when Cadmium (Cd) is introduced into chalcogenide glass, the concentration of Dy(3+) ions doped in GeGaCdS glasses is markedly increased, the thermodynamic performance improves, and the difference between T(g) and T(x) is >120 degrees C. The Vickers microhardness is also modified greatly, about 245 kgf/mm(2). The optical spectra indicate that all absorption and emission bands of Dy(3+) are clearly observed and red-shifted with increasing Dy(3+) concentration.