A5037805780- Glass properties and applications
- Thermography and Photoacoustic Techniques
- Luminescence Properties of Advanced Materials
- Pigment Synthesis and Properties
- Phase-change materials and chalcogenides
- Solid State Laser Technologies
- Calibration and Measurement Techniques
- Laser Material Processing Techniques
- Magnetic and transport properties of perovskites and related materials
- Surface Roughness and Optical Measurements
- Recycling and utilization of industrial and municipal waste in materials production
- Optical and Acousto-Optic Technologies
- Multiferroics and related materials
- Nuclear materials and radiation effects
- Ferroelectric and Piezoelectric Materials
- Mineralogy and Gemology Studies
- Lanthanide and Transition Metal Complexes
- Rare-earth and actinide compounds
- Photoacoustic and Ultrasonic Imaging
- Photorefractive and Nonlinear Optics
- Electrical and Thermal Properties of Materials
- Chemistry Education and Research
- Thermal Expansion and Ionic Conductivity
- Advanced optical system design
- Material Science and Thermodynamics
State University of Norte Fluminense
2010-2023
Centro de Tecnologia Mineral
2023
United States Department of Energy
2009
Universidade Estadual de Campinas (UNICAMP)
1997-2005
Ames National Laboratory
2005
Iowa State University
2005
Universidade de São Paulo
1998-2003
Universidade Federal de São Carlos
1999-2003
An absolute thermal lens method to determine fluorescence quantum efficiency and concentration quenching of solids is described in this work. The low silica calcium aluminate glasses doped with different concentrations neodymium dioxide melted under vacuum conditions remove water has been measured by using mode-mismatched spectrometry. It shown that the signal amplitude linearly dependent on up 4.0 wt %, changing significantly from 4.5 5.0 indicating there was only above % dioxide....
In this letter, we investigate the midinfrared photoluminescence of a series diode-pumped Er3+-doped and Er3+, Yb3+-codoped low-silica content aluminosilicate glasses. Emission at 2.8 μm was observed in both single doped codoped samples. The effect Yb3+ codoping samples such that, for example, 2 wt % Er3+-doped, yield found to be roughly three times larger than that sample. This behavior attributed efficient sensitization Er3+ by our oxide based host results reported together with...
The effects of Nd2O3 doping on the thermal and mechanical properties vacuum melted, low silica, calcium aluminosilicate glasses are presented. For doped glasses, vitrification limit was found to correspond a maximum load 5 wt % Nd2O3. influence rare earth diffusivity, conductivity, Vickers hardness such that all these physical parameters decreased by roughly same amount, namely 8%, between undoped sample. dependence parameters, as function doping, strongly supports idea Nd3+ act network modifiers.
In this work, Eu3+-doped lead borosilicate glasses (SiO2–B2O3–PbO2) synthesized by fusion method had their optical properties investigated as a function of temperature. Atomic Force Microscopy images obtained for glass matrix annealed at 350 and 500 °C show precipitated crystalline phase with sizes 11 21 nm, respectively. Besides, the temperature increases from to 300 K strong Eu3+ photoluminescence (PL) enhancement takes place. This anomalous feature is attributed thermally activated...
In this paper, a broad combined orange-red emission from Eu²⁺- and Eu³⁺-doped low-silica calcium aluminosilicate (LSCAS) glass is reported. Spectroscopic results demonstrate that it possible to tune the wavelength by changing excitation in UV-Vis region. The color coordinates for spectra were calculated, using Commission Internationale de l'Éclairage 1931 1976 chromatic diagrams, note they are dependent on wavelength. addition, (u', v') investigated LSCAS samples close Planckian spectrum...
The $2.8\ensuremath{-}\ensuremath{\mu}\mathrm{m}$ emission of ${\mathrm{Er}}^{3+}$-doped low silica content calcium aluminate glasses sensitized by ${\mathrm{Yb}}^{3+}$ is investigated using conventional spectroscopy. experimental data are quantitatively analyzed in terms the energy transfer among and ${\mathrm{Er}}^{3+}$ ions. rate dipole-quadrupole mechanism was inferred to be larger than dipole-dipole mechanism. Using Dexter model transfer, microscopic parameters were calculated. It found...
The optical, magnetic and structural properties of Eu doped low silica calcium aluminosilicate glasses were investigated. optical absorption coefficient presented two bands at 39 246 29 416 cm−1, which assigned respectively to the , transitions Eu2+. fluorescence measured 300 K on a sample with 0.5 wt% Eu2O3 exhibited broad band centered 17 350 is attributed transition Eu2+, whereas additional peaks are due Eu3+. From magnetization XANES data it was possible evaluate fractions Eu2+ Eu3+ for...
Temperature-dependent and frequency-dependent dielectric investigations have been performed in TbMnO3 polycrystals sintered either oxidative or reductive atmospheres. The results revealed the occurrence of two anomalies above 100 K, which are caused by thermal activation charge carriers their motion grain cores boundaries. temperature dependence bulk dc conductivity was also analysed indicates that move between inequivalent sites according to a variable-range-hopping mechanism. Also, strong...
Erbium and ytterbium environments in low-silica calcium aluminate glasses, with nominal composition 58 CaO, $27.1\ensuremath{-}x$ ${\mathrm{Al}}_{2}{\mathrm{O}}_{3},$ 6.9 MgO, 8 ${\mathrm{SiO}}_{2},$ x ${\mathrm{Er}}_{2}{\mathrm{O}}_{3},$ or ${\mathrm{Yb}}_{2}{\mathrm{O}}_{3},$ $0.2<~x<~1.5(\mathrm{mol}%),$ were investigated using x-ray-absorption fine-structure spectroscopy (EXAFS) on the Er Yb ${L}_{\mathrm{III}}$ edge. The average Er-O bond separation was found to vary only slightly...