Five-fold twinned β-PbF2 nanocrystals in oxyfluoride glass ceramics

Transparent oxyflouride glass ceramics composed of SiO2–Al2O3–Na2O–NaF–YF3 tri-coped with Nd3+/Yb3+/Ho3+ were prepared by thermal treatment. Segregation of NaYF4 nanocrystals in the matrix was confirmed from structural analysis by means of X-ray diffraction and transmission electron microscopy. Compared with glass samples, very strong green upconversion (UC) luminescence due to the Ho3+:(4F5, 5S2)→5I8 transition was observed in the glass ceramics under 808 nm excitation. It was found that upconversion intensity of Ho3+ strongly depends on the Nd3+ concentration, and the energy transfer process from Nd3+ to Ho3+ via Yb3+ was proposed.

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Formation of Eu-Doped CaF2 Naonocrystals in Glass-Ceramics by Infrared Laser Irradiation

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.749.211 ◽

2015 ◽

Vol 749 ◽

pp. 211-214

Author(s):

Dong Seon Kim ◽

Jin Ho Lee ◽

Ki Soo Lim

Keyword(s):

Glass Ceramics ◽

Dopant Distribution ◽

X Ray Diffraction ◽

Oxyfluoride Glass ◽

Strong Emission ◽

X Ray ◽

Exposed Region ◽

Crystalline Environment ◽

Confocal Fluorescence ◽

Infrared Laser Irradiation

Glass-ceramic was precipitated on the oxyfluoride glass surface by thermal annealing with a CO2 laser and a heat gun. Micro x-ray diffraction showed the formation of CaF2 ain the exposed region to the laser. Dopant distribution in glass ceramics was probed by confocal fluorescence microscope by observing much strong emission from Eu ions than the glassy area under 405 nm excitation. Much enhanced visible emissions under 365 nm excitation also showed well incorporation of Eu3+ ions into a crystalline environment.

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Nucleation efficiency of erbium and ytterbium fluorides in transparent oxyfluoride glass-ceramics

Journal of Materials Research ◽

10.1557/jmr.2005.0051 ◽

2005 ◽

Vol 20 (2) ◽

pp. 472-481 ◽

Cited By ~ 43

Author(s):

G. Dantelle ◽

M. Mortier ◽

D. Vivien ◽

G. Patriarche

Keyword(s):

Cell Parameter ◽

Glass Ceramics ◽

Parameter Study ◽

X Ray Diffraction ◽

Oxyfluoride Glass ◽

X Ray ◽

Oxyfluoride Glasses ◽

Transmission Electron ◽

Optical Applications ◽

Co Doped

Oxyfluoride glasses (GeO2–PbO–PbF2) doped with erbium and/or ytterbium fluorides were prepared. Highly transparent glass-ceramics, containing β–PbF2 nanocrystallites, were successfully obtained by controlled glass devitrification and were studied as they could lead to promising optical applications. To characterize the samples, differential thermal analysis, x-ray diffraction, and transmission electron microscopy were performed, revealing a variation of the crystallites size, the crystallites number and β–PbF2 crystallization temperature according to the doping ion. Indeed, the analyses indicated differences between erbium and ytterbium fluorides in promoting the crystallization of the fluoride phase. Although both fluorides act as seeds for β–PbF2 heterogeneous nucleation, erbium fluoride has higher nucleation efficiency than ytterbium fluoride and runs the nucleation process in co-doped samples. Energy dispersive x-ray microanalysis insured high rare-earth segregation into the crystallites, proving the formation of a solid solution Pb1−x−yErxYbyF2 +x+y, also confirmed by the unit cell parameter study.

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Superconducting Properties of Bi-Sr-Ca-Cu-O Crystallized Glass

International Journal of Modern Physics B ◽

10.1142/s0217979299000837 ◽

1999 ◽

Vol 13 (09n10) ◽

pp. 985-989

Author(s):

S. Chudinov ◽

S. Stizza ◽

B. Kościelska ◽

L. Murawski ◽

W. Sadowski ◽

...

Keyword(s):

Magnetic Field ◽

Glass Ceramics ◽

Superconducting Phase ◽

Superconducting Transition ◽

Resistive Transition ◽

Superconducting Properties ◽

X Ray Diffraction ◽

Melt Quenching ◽

X Ray ◽

Quenching Method

This paper reports the crystallization and superconducting properties of Bi 4 Sr 3 Ca 3 Cu 4 O x glass-ceramics. The glass was prepared using the conventional melt-quenching method. X-ray diffraction pattern has shown that the annealing at temperature of 800°C converted the glass into glass-ceramics with Bi 2 Sr 2 CaCu 2 O x superconducting phase (2212-phase). The superconducing transition exhibits the change in the slope that is characteristic for two different superconducting phases. It is observed that T c (zero) increases from 20 K to 80 K with increasing time of annealing. The influence of magnetic field on the superconducting transition has been investigated. Our studies revealed a remarkable broadening of the resistive transition as a function of temperature with increasing field. The temperature width ( T c-T) of the transition for both phases increases with magnetic field according to Tinkham model.

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X-Ray Diffraction and Raman Spectroscopic Studies of Glasses and Glass-Ceramics Inside the A2O-MoO3-Nb2O5-P2O5 (A= Li, Na) Systems

Eurasian Chemico-Technological Journal ◽

10.18321/ectj46 ◽

2010 ◽

Vol 12 (3,4) ◽

pp. 207

Author(s):

H. Bih ◽

L. Bih ◽

M.P.F. Graça ◽

M.A. Valente ◽

B. Elouadi

Keyword(s):

Glass Ceramics ◽

Spectroscopic Studies ◽

Phosphate Glasses ◽

Molar Ratio ◽

Thermal Treatments ◽

X Ray Diffraction ◽

X Ray ◽

Raman Spectroscopic ◽

Heat Treated ◽

Quenching Method

Phosphate glasses in the system (50-x)A2O-xMoO3-10Nb2O5-40P2O5 (AMo-40), with x=0; 30 and A=Li or Na were prepared by the melt quenching method. The effect in the crystallization behaviour of the glass due to the introduction of MoO3 in the glass composition and varying the molar ratio between network modifiers and network formers (M/F) was studied. The prepared glasses were heat-treated in air, at 550, 600 and 650 ºC for 4 hours. The structure, of the obtained samples, was studied by differential thermal analysis (DTA), X-ray powder diffraction (XRD), Raman spectroscopy and the morphology by scanning electron microscopy (SEM). It was found that the replacement of Li2O or Na2O by MoO3 reduces the number of the crystallised phases. In the lithium-niobiophosphate glasses the presence of MoO3 promotes the formation of NbOPO4 and reduces the formation of ortho- and pyro-phosphate phases. The thermal treatments affect the arrangements of the network structure of the AMo-40-glasses.

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Formation of nanostructures in Eu3+ doped glass–ceramics: an XAS study

Acta Crystallographica Section A Foundations and Advances ◽

10.1107/s2053273314090408 ◽

2014 ◽

Vol 70 (a1) ◽

pp. C959-C959

Author(s):

Julio Pellicer-Porres ◽

Alfredo Segura ◽

Gema Martínez-Criado ◽

Ulises Rodríguez-Mendoza ◽

Víctor Lavín

Keyword(s):

Amorphous Phase ◽

Glass Ceramic ◽

Glass Ceramics ◽

Aluminosilicate Glass ◽

Chemical Information ◽

Nanocrystalline Phase ◽

X Ray Diffraction ◽

Oxyfluoride Glass ◽

X Ray ◽

X Ray Absorption

Lead-aluminosilicate oxyfluoride transparent glass–ceramics doped with RE3+ ions have been revealed to be unique in the field of optical material engineering. This kind of material consists of a beta_x000C_-PbF2 fluoride nanocrystalline phase in an aluminosilicate glassy amorphous phase. In this way, the macroscopic properties of this material are characteristic of aluminosilicate glass, whereas the spectroscopic properties of the RE3+ ions remain those of low-phonon-energy fluoride crystals. The optical properties of the RE3+ ions, and therefore their interest for photonic applications, depend on the final environment of these ions in a host matrix. Exploration of the local structure of the Eu3+ ions as well as characterization of the amorphous matrix demands structural techniques that do not rely on long range order. Given the complexity of the system under study, chemical selectivity is also required. In this work [1], we describe the results of x-ray absorption experiments carried out to deduce structural and chemical information in Eu3+ doped, transparent, oxyfluoride glass and nanostructured glass–ceramic samples. The spectra were measured at the Pb and Eu–LIII edges. The Eu environment in the glass samples is observed to be similar to that of EuF3. Complementary x-ray diffraction experiments show that thermal annealing creates _x000C_beta-PbF2 type nanocrystals. X-ray absorption indicates that Eu ions act as seeds in the nanocrystal formation. There is evidence of interstitial fluorine atoms around Eu ions as well as Eu dimers. X-ray absorption at the Pb–LIII edge shows that after the thermal treatment most lead atoms form a PbO amorphous phase and that only 10% of the lead atoms remain available to form _x000C_beta-PbF2 type nanocrystals. Both x-ray diffraction and absorption point to a high Eu content in the nanocrystals. Our study suggests new approaches to the oxyfluoride glass–ceramic synthesis in order to further improve their properties.

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Electrical Characteristics of Bismuth Titanate Ceramics and Glass-Ceramics, Containing SiO2 and Nd2O3 as Additives

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.538.233 ◽

2013 ◽

Vol 538 ◽

pp. 233-237 ◽

Cited By ~ 1

Author(s):

Stanislav S. Slavov ◽

Milena Z. Krapchanska ◽

Elena P. Kashchieva ◽

Svetlin B. Parvanov ◽

Yanko B. Dimitriev

Keyword(s):

Bismuth Titanate ◽

Glass Ceramics ◽

Dielectric Losses ◽

Electrical Characteristics ◽

X Ray Diffraction ◽

Graphite Electrodes ◽

X Ray ◽

Quenching Method ◽

Titanate Ceramics ◽

Thermal Stability Of

Bismuth-titanate ceramics containing SiO2and Nd2O3as additives are synthesized by melt quenching method in the system Bi2O3-TiO2-Nd2O3-SiO2at temperature 1450 oC. By X-ray diffraction analysis are determined the crystal phases participating in the materials: Bi4Ti3O12, Bi12TiO20and δ-Bi2O3. The addition of SiO2allows to control the glass formation ability of the supercooled melts. The addition of Nd2O3stimulates the thermal stability of the materials due to formation of solid solutions Bi4-xNdxTi3O12. Measurements of the electrical conductivity, capacitance and dielectric losses of selected samples are performed by DC resistible bridge and digital capacity meter (with frequency of 1 kHz) using two-terminal method and a suitable sample holder with graphite electrodes. It is established that for the investigated samples the activation energy of conductivity is in the range 1 – 1,3 eV, dielectric permittivity from 1000 to 3000 at (at 400 oC) and dielectric losses tgδ are between 0,0002 and 0,1.

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Influence of NiO Nanoparticles on Physical Properties of TiO2 Doped Magnesium Ultra-Phosphate Glass-Ceramics

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1107.32 ◽

2015 ◽

Vol 1107 ◽

pp. 32-37

Author(s):

S.F. Abd Rahman ◽

M.R. Sahar ◽

Sib Krishna Ghoshal

Keyword(s):

Physical Properties ◽

Glass Ceramics ◽

Nio Nanoparticles ◽

X Ray Diffraction ◽

Xrd Pattern ◽

X Ray ◽

Amorphous Nature ◽

Quenching Method ◽

Nio Nps ◽

Controlled Doping

Tuning the physical properties of inorganic glass-ceramics through controlled doping of magnetic nanoparticles is topically challenging. A series of glass-ceramic having chemical composition 75P2O5-17MgO-(3-x)TiO2-5Li2O with x = 0 to 3 mol% containing nickel oxide (NiO) nanoparticles (NPs) are prepared by melt quenching method (MQT) via heat treatment at 350 °C. The effect of NiO NPs on thermal and magnetization response are examined. X-Ray Diffraction (XRD) pattern confirm the amorphous nature of the samples. Differential Thermal Analysis (DTA) measurement shows the decrement of glass stability from 327°C to 295°C with the increase of titanium dioxide (TiO2) contents which are glass seem to be unstable. Significant increase in the magnetization is evidenced with the increase of NiO nanoparticles from 1.5 mol% to 2 mol%. The improved physical properties of these glass-ceramics suggest their usefulness in photo-electronic.

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Characterization of Nanoporous Lanthanide-Doped Gadolinium Gallium Garnet Powders Obtained by Propellant Synthesis

Materials Science Forum ◽

10.4028/www.scientific.net/msf.494.143 ◽

2005 ◽

Vol 494 ◽

pp. 143-148 ◽

Cited By ~ 13

Author(s):

R. Krsmanović ◽

Stefano Polizzi ◽

P. Canton

Keyword(s):

Lanthanide Ions ◽

Nanocrystalline Powders ◽

Gadolinium Gallium Garnet ◽

Phase Identification ◽

Gravimetric Analysis ◽

X Ray Diffraction ◽

X Ray ◽

Trivalent Lanthanide ◽

High Degree

In the present work we study the nanocrystalline powders of lanthanide-doped Gd3Ga5O12 (GGG, gadolinium gallium garnet) prepared using propellant synthesis. A series of GGG samples containing a number of different trivalent lanthanide ions (Tm, Er, Ho, Eu, Sm, Nd, and Pr) in different quantities (1%, 5%, 10%) were produced. Samples were characterized by X-ray diffraction (pre- and post calcination) for phase identification and line-broadening analysis, and by electron microscopy (SEM and TEM) for morphological and nanostructural investigation. Thermal behavior of the powder was investigated by thermal gravimetric analysis (TGA) and differential thermal analysis (DTA). The samples have a polycrystalline porous structure. Elemental microanalysis made by energy dispersive X-ray spectroscopy (EDX) detector attached to TEM and XRD unit-cell determinations confirmed that the lanthanides ions entered the structure of GGG. Crystallites have a high degree of disorder.

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In Situ X-Ray Diffraction Studies of Crystallization Growth Behavior in ZnO-Bi2O3-B2O3 Glass as a Route to Functional Optical Devices

MRS Advances ◽

10.1557/adv.2017.640 ◽

2018 ◽

Vol 3 (11) ◽

pp. 563-567 ◽

Cited By ~ 1

Author(s):

Quentin Altemose ◽

Katrina Raichle ◽

Brittani Schnable ◽

Casey Schwarz ◽

Myungkoo Kang ◽

...

Keyword(s):

Heat Treatment ◽

Glass Ceramics ◽

Treatment Temperature ◽

Crystal Phase ◽

X Ray Diffraction ◽

X Ray ◽

In Situ Xrd ◽

Dsc Measurements ◽

Transmission Window

ABSTRACTTransparent optical ZnO–Bi2O3–B2O3 (ZBB) glass-ceramics were created by the melt quenching technique. In this work, a melt of the glass containing stoichiometric ratios of Zn/Bi/B and As was studied. Differential scanning calorimeter (DSC) measurements was used to measure the thermal behavior. VIS/NIR transmission measurements were used to determine the transmission window. X-ray diffraction (XRD) was used to determine crystal phase. In this study, we explore new techniques and report a detailed study of in-situ XRD of the ZBB composition in order to correlate nucleation temperature, heat treatment temperature, and heat treatment duration with induced crystal phase.

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