Spectroscopic and magnetic behaviour of xGd2O3 (1 − x)(Bi2O3·PbO) glasses

doi:10.1016/j.mseb.2004.06.001

Materials Science and Engineering: B

Volume 112, Issue 1, 15 September 2004, Pages 59-63

https://doi.org/10.1016/j.mseb.2004.06.001 Get rights and content

Abstract

Glasses of the xGd₂O₃ (1 − x)(Bi₂O₃·PbO) system (0 ≤ x ≤ 0.15) were obtained and studied by IR spectroscopy, electron paramagnetic resonance (EPR), magnetic susceptibility and density measurements. IR data show that increasing the amount of gadolinium ions in the studied glasses produces structural modifications of the host vitreous matrix consisting in a conversion of the [BiO₃] into [BiO₆] structural units. EPR and magnetic susceptibility data show that for low gadolinium oxide content of the samples, x ≤ 0.05, the Gd³⁺ ions are randomly distributed in the host glass matrix and are present only as isolated species. For higher gadolinium oxide contents of the samples, x > 0.05, the Gd³⁺ ions appear as both isolated and antiferromagnetically coupled species. IR and density measurements support the assumption of the network modifier role played by the gadolinium ions in the xGd₂O₃ (1 − x)(Bi₂O₃·PbO) glasses. EPR data show an unusual absorption line for the Gd³⁺ ions in glass matrices. This absorption line is due to Gd³⁺ ions that replace Bi³⁺ and Pb⁴⁺ ions from the host glass matrix and play the network former role in the studied glasses.

Introduction

Glasses containing rare-earth ions have attracted a great deal of interest due to their important applications for optical telecommunication, laser technology and immobilization of radioactive materials [1], [2], [3]. Considerable interest was accorded to glasses containing gadolinium ions. Electron paramagnetic resonance (EPR) and magnetic susceptibility measurements performed on such glasses reveal interesting and sometimes contradictory aspects concerning the nature of magnetic interactions between the gadolinium ions and the distribution of these ions in the glass host matrix [4], [5], [6], [7], [8], [9], [10].

On the other hand, unconventional novel oxide glasses based on Bi₂O₃ have gained a large interest due to their interesting physical properties (high density, low bond strength, high polarizability, long IR cut-off, high nonlinear optical susceptibility) leading to important potential applications as nonlinear optical materials, low loss optical fibres, IR transmitting windows, thermal and mechanical sensor, etc. [3], [11], [12], [13], [14], [15], [16], [17]. Because of the low field strength of the Bi³⁺ ions, Bi₂O₃ was not considered as a network former oxide. However, in combination with other oxides (B₂O₃, PbO, TeO, etc.) glass formation is possible in a relatively large composition range [14] due to the high polarizability of the Bi³⁺ cation [15]. The interest for this unconventional network forming oxide is amplified by the fact that bismuth is known to appear in the glass matrices in more than one stable coordination states having the possibility to generate several types of structural units.

In order to extend the available information concerning the interesting class of bismuthate glasses containing gadolinium ions, in this work we investigated the xGd₂O₃ (1 − x)(Bi₂O₃·PbO) vitreous system with 0 ≤ x ≤ 0.15 by IR spectroscopy, EPR, density and magnetic susceptibility measurements.

Section snippets

Experimental

Samples of the the xGd₂O₃ (1 − x)(Bi₂O₃·PbO) vitreous system (noted GBP) with x = 0, 0.01, 0.03, 0.05, 0.07, 0.10 and 0.15 were obtained using reagent grade Bi₂O₃, PbO and Gd₂O₃. The mentioned oxides were mixed in suitable proportions to obtain the desired compositions. The mixtures were milled in an agate ball mill for 30 min and then were melted at 1250 °C for 15 min. The glass samples were obtained by pouring the melts on a stainless steel block.

X-ray diffraction investigation of the samples

Results and discussion

Infrared spectroscopy was used to obtain essential information concerning the arrangement of the structural units of the xGBP glasses. Fig. 1 shows the infrared absorption spectra recorded for these glasses.

A simple inspection of the spectral features presented in Fig. 1 shows that they are those characteristic of the base glass matrix, Bi₂O₃·PbO and no dramatic changes occur with increasing the Gd₂O₃ content, x, of the samples. This suggests that, in general, the studied xGBP vitreous system

Conclusions

The IR study of the xGBP glasses show that the gadolinium ions play a network modifier role in this vitreous system. Thus, increasing the gadolinium content of the studied glasses generates structural changes consisting mainly in a conversion of [BiO₃] into [BiO₆] structural units. Density data obtained for the xGBP glasses are in good agreement with this assumption.

The EPR study of the xGBP glasses shows a distribution of gadolinium ions in two types of locations. The first one, specific for

Acknowledgements

The partial financial support of the Romanian Ministry of Education (grant CNCSIS 415/2003) is greatly acknowledged by two of the authors (E.C. and L.P.).

References (31)

M.J. Weber
J. Non-Cryst. Solids
(1980)
D.I. Griscom
J. Non-Cryst. Solids
(1980)
I. Ardelean et al.
J. Non-Cryst. Solids
(1992)
E. Culea et al.
J. Magn. Magn. Mater.
(1996)
S. Simon et al.
Solid State Commun.
(2000)
K. Gerth et al.
J. Non-Cryst. Solids
(1997)
B. Karthikeyan et al.
Phys. B
(2003)
F. Miyaji et al.
J. Non-Cryst. Solids
(1990)
V. Dimitrov et al.
J. Non-Cryst. Solids
(1994)
Yi Hu et al.
Mater. Chem. Phys.
(1997)

L. Baia et al.

J. Non-Cryst. Solids

(2002)

B. Karthikeyan et al.

Phys. B

(2003)

T. Watanabe et al.

J. Non-Cryst. Solids

(2002)

T. Ristoiu et al.

Mater. Lett.

(1999)

E. Culea et al.

Mater. Sci. Eng. B

(1999)

Cited by (72)

Crystallization kinetics and structural development of Bi<inf>2</inf>GeO<inf>5</inf> glass-ceramics fabricated by the modified incorporation technique
2024, Optik
This study focuses on the fabrication and crystallization kinetics of bismuth germanate (Bi₂GeO₅) crystals in glass ceramics. Bismuth germanate glass-ceramics were produced from a base glass containing 58.4 mol% Bi₂O₃, 23.4 mol% GeO₂, and 18.2 mol% B₂O₃ using a modified incorporation technique. Differential thermal analysis was used to determine the crystallization temperature. The X-ray diffraction results showed a dominant peak corresponding to the pure Bi₂GeO₅ phase, which has an orthorhombic crystal structure. The local Avrami exponent (n(x)) and local crystallization activation energy (E_c(x)) were determined using a non-isothermal method with heating rates ranging from 5 to 20 °C/min. The results indicated that the crystal growth process of the glass-ceramics occurred in all three dimensions, with Avrami exponent values ranging from 1.79 to 2.5. The microstructure also revealed uniform crystallization across the surface and bulk diffusion of crystallites. The modified incorporation method successfully enhanced the crystallization of Bi₂GeO₅ glass-ceramics, resulting in the transition from one-dimensional needle-like crystals to the desired crystal dimensions.
Photoluminescence and EPR investigation in ZnO: Gd3+, Yb3+ phosphors for application in light emitting diode
2023, Materials Science in Semiconductor Processing
The zinc oxide (ZnO) phosphors co-doped with Gd³⁺/Yb³⁺ have been synthesised using the solid-state reaction method. The compound ZGYO { $Z n_{(1 - 1.5 x - 1.5 y)} G d_{x} Y b_{y} O$ } is prepared for different molar concentrations of Yb (y) = 0.00, 0.01, 0.03, 0.05 and Gd (x) fixed at 0.01. The XRD analysis confirms the hexagonal phase of the ZnO wurtzite structure. The EDX and XPS spectra confirm the incorporation of Gd³⁺ and Yb³⁺ in the ZnO lattice successfully. The crystallite sizes of the prepared samples calculated from XRD data were in the range (300–600) nm. Studies of Raman, photoluminescence (PL) and electron paramagnetic resonance (EPR) substantiate crystalline defects in the prepared phosphors. The EPR spectrum recorded (at 298K and 77K) is characterised by different crystal field interactions resembling the ‘U’ spectrum. EPR line broadening and the presence of clusters are observed in 3% and 5% Yb³⁺ co-doped phosphors, which can be attributed to the short lattice relaxation of Yb³⁺ ions present as clusters in the host matrix. Blue and green emissions dominate the visible region of the PL spectra and have been observed due to changes in the concentration of interstitial and vacancy defects. We have mathematically evaluated the performance of the ZnO phosphors co-doped with Gd³⁺/Yb³⁺ as an alternate emissive layer in LED. Our work has demonstrated the potential use of the material to fabricate an energy-efficient LED.
Local structural effects of Gd3+ ions incorporation in shell of nanostructured silica core – alumina rich shell microspheres
2023, Journal of Molecular Structure
Non-crystalline nanostructured silica core – alumina rich shell microspheres, with Gd ions in the shell were obtained by sol-gel procedure following a synthesis route based on the Stöber method. The samples were characterized by DTA/TGA, XRD, SEM and TEM, EPR, solid-state NMR and XPS techniques. The effect of increasing Gd ions content on the local structure in alumina rich shell and at its interface with silica core was investigated. It was also found that increasing the concentration of the paramagnetic ions leads to a modification of the local magnetic field at sites of neighboring aluminum and silicon ions. Gadolinium ions are distributed in the aluminum sites from alumina rich shell. As result of increasing the gadolinium incorporation at the core-shell interface the diffusion of aluminum in the silica network, as well as the migration of the silicon in the alumina rich shell, are enhanced. Therefore, Si-O-Al bridges are formed at the interface, leading to stable non-crystalline structures, with Gd ions on the external layer of the shell, as proved by XPS, having potential application as contrast agents for magnetic resonance imaging (MRI).
On the ultraviolet B emissions of CaLaB<inf>7</inf>O<inf>13</inf>:Gd3+ phosphor
2020, Optik
CaLaB₇O₁₃ doped with trivalent gadolinium (Gd³⁺) ions was prepared by the sol-gel technique with varying concentration of Gd³⁺. X-ray diffraction (XRD) analysis confirmed the formation of the prepared phosphors. The phosphors were characterized by the photoluminescence (PL) spectroscopy, where PL intensity increases by increasing the Gd³⁺ ions in the CaLaB₇O₁₃ matrix. Emission bands at 307 nm and 313 nm correspond to ⁶P_5/2 → ⁸S_7/2 and ⁶P_7/2 → ⁸S_7/2 transitions, respectively. Further, the phosphor with 0.09 mol of Gd³⁺ had the highest emission among different concentration of Gd³⁺ ions and decreased with further doping. Concentration quenching was owing to multipole-multipole interaction among the dopant ions. The Electron paramagnetic resonance (EPR) spectra confirmed the existence of Gd³⁺ ions in the prepared phosphors and exhibit the characteristic gadolinium U type spectrum.
Photoluminescence properties and energy transfer investigations of Gd3+ and Sm3+ co-doped ZnO–BaO–TeO<inf>2</inf> glasses for solid state laser application
2020, Journal of Luminescence
The physical, optical, photoluminescence properties of (54-x) TeO₂ − 10ZnO − 35BaO − 1Sm₂O₃ − xGd₂O₃, where 0 ≤ x ≤ 3 (mol %) are investigated in this research. Five samples of glass were produced by the normal melt quenching process. The evidence indicates that the density of glass increased with increasing of Gd₂O₃. The molar volume and refractive index investigations have been used to consider the physical properties and optical properties of the produced glass system. Physical parameters such as polaron radius, inter-ionic radius and field strength for Sm³⁺/Gd³⁺ ions have been evaluated. The absorption spectra of glass contain peaks at 358, 404, 948, 1,085, 1,235, 1,385, 1490 and 1535 nm corresponding to the transitions from ⁶H_5/2 to ⁴D_3/2, ⁶P_3/2, ⁶F_11/2, ⁶F_9/2, ⁶F_7/2, ⁶F_5/2, ⁶F_3/2, and ⁶H_15/2, respectively. The emission spectra of glass show four bands at found and attributed to 563, 604, 646 and 709 nm by excitation at 275 nm. Judd-Ofelt parameters and radiative properties was investigated for 53.5TeO₂ − 10ZnO − 35BaO − 1Sm₂O₃ − 0.5Gd₂O₃ glass. Energy transfer characteristics was observed in the present glasses. The emission intensity of Sm³⁺ increased with increasing of Gd₂O₃ concentration until 2 mol %, while the luminescence lifetime decreases with increasing of Gd₂O₃ content.
Structure and EPR investigations on Gd3+ ions in magnesium-lead-borophosphate glasses
2020, Journal of Molecular Structure
Gadolinium (Gd³⁺)-doped magnesium-lead-borophosphate glasses composed of MgHPO₄–PbO–B₂O₃–Gd₂O₃ (PPbBMgGd) were fabricated by usual melt-quenching approach. The physical properties such as refractive index (n), density (ρ) and molar volume (V_m) were attained. Thermal analysis of the glass has been performed through differential scanning calorimetry (DSC). Raman, Fourier transform infrared (FTIR), Electron Paramagnetic Resonance (EPR) and steady-state luminescence of PPbBMgGd glasses were investigated. The Raman and FTIR spectra explore the vibrational groups of both phosphate and borate networks in the PPbBMgGd glasses. The EPR spectra display three characteristic signals at room temperature with definite g values of 6.2, 2.8 and 2.0. These characteristic signals were ascribed perhaps the Gd³⁺ ions that are located respectively at feeble, moderate and sturdy cubic symmetry sites. Moreover, the EPR spectra were also obtained at various low temperatures (123–297 K) for 5.0 mol% of Gd³⁺-doped PPbBMgGd5.0 glass. Difference in population among the Zeeman levels (N) and paramagnetic susceptibility (χ) were evaluated. Photoluminescence spectrum reveals a broad intense band of Gd³⁺ ions upon excitation at 278 nm, could be suitable for visible broadband applications.

View all citing articles on Scopus

View full text

Article preview

Materials Science and Engineering: B

Abstract

Introduction

Section snippets

Experimental

Results and discussion

Conclusions

Acknowledgements

References (31)

J. Non-Cryst. Solids

J. Non-Cryst. Solids

J. Non-Cryst. Solids

J. Magn. Magn. Mater.

Solid State Commun.

J. Non-Cryst. Solids

Phys. B

J. Non-Cryst. Solids

J. Non-Cryst. Solids

Mater. Chem. Phys.

J. Non-Cryst. Solids

Phys. B

J. Non-Cryst. Solids

Mater. Lett.

Mater. Sci. Eng. B

Cited by (72)

Crystallization kinetics and structural development of Bi<inf>2</inf>GeO<inf>5</inf> glass-ceramics fabricated by the modified incorporation technique

Photoluminescence and EPR investigation in ZnO: Gd<sup>3+</sup>, Yb<sup>3+</sup> phosphors for application in light emitting diode

Local structural effects of Gd<sup>3+</sup> ions incorporation in shell of nanostructured silica core – alumina rich shell microspheres

On the ultraviolet B emissions of CaLaB<inf>7</inf>O<inf>13</inf>:Gd<sup>3+</sup> phosphor

Photoluminescence properties and energy transfer investigations of Gd<sup>3+</sup> and Sm<sup>3+</sup> co-doped ZnO–BaO–TeO<inf>2</inf> glasses for solid state laser application

Structure and EPR investigations on Gd<sup>3+</sup> ions in magnesium-lead-borophosphate glasses