Maria Bosca

Preparation and structural characterization of some Fe2O3-B2O3-ZnO glasses and glass ceramics

X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy have been employed to investigate the (Fe2O3)x?(B2O3)(60-x)?(ZnO)40 samples, with 0 ? x ? 20 mol%. The samples have been prepared by melting at 1100 ?C for 10 minutes followed by rapid cooling at room temperature. The structure of samples was analyzed by means of XRD. XRD pattern show that the sample without iron ions and the samples contained 3 and 5 mol% were glasses. For samples contain 10, 15 and 20 mol% Fe2O3 it obtains glass ceramics. These glass ceramics contains a unique crystalline phase, zinc ferrite (ZnFe2O4), embedded in an amorphous matrix. FTIR spectroscopy data suggest that for the glass samples the iron ions play the network modifier role. These data show that the glass network consists of BO3 and BO4 structural units. For glass ceramics samples FTIR spectra show characteristic bands of ZnFe2O4.

FTIR spectroscopic study of some lead germanate glasses

The structures of two lead germante glasses – yGeO2(100-y)PbO and xNd2O3(100-x)[GeO2PbO] – are investigated by the Fourier transform infrared (FTIR) spectroscopy. The structural role of germanium, lead and neodymium ions is discussed. The presence of GeO4, GeO6 and PbO4 structural units was evidenced in the studied glass networks. In the case of the xNd2O3(100-x)[GeO2PbO] glasses it was shown that the ratio of the mentioned structural units depends on the Nd2O3 content of the samples. Therefore Nd2O3 play the network modifier role in studied glasses.

Structural and physical characteristics of xGd2O3(100-x)[Bi2O3 B2O3] glasses

A study on the xGd2O3(100-x)[Bi2O3 B2O3] glass system where 0 < x ≤ 30 mol% was carried by using X-ray diffraction, FTIR spectroscopy and density measurements. The relationships between composition and properties were demonstrated. The results indicate that Gd2O3 play a network modifier role and stabilizes the structure of the vitreous matrix.

Immobilization of gadolinium in borate-tellurate glasses

Glasses in the xGd2O3?(100-x)[6TeO2?4B2O3] system, where x = 0, 5, 10, 15, 25 and 30 mol%, have been prepared from melt quenching method. The structural changes were studied by FTIR spectroscopy and DFT calculations. The FTIR spectroscopy data for these systems show that the gadolinium ions have a strong affinity towards the structural units containing non-bridging oxygens, which are negative-charged, because they are readily available for charge compensation. So that, it seems that the content of [BO4] structural units cannot become higher, because the modified [BO3] units containing one or more B-O-Gd bonds are unable to accept a fourth oxygen atom. On the other hand, the gadolinium ions have also an affinity pronounced towards [TeO3] structural units yielding the deformation of the Te-O-Te linkages. The compositional evolution of the network was accommodated with excess of oxygen by the formation of orthoborate structural units, disintegration of some boroxol rings and radical rearrangement of the network formed by the [TeO6] octahedral units.

ER-DOPED LEAD–BISMUTHATE GLASSES: MAGNETIC AND STRUCTURAL PROPERTIES

The effect of erbium-doping on the structural and magnetic properties of the xEr2O3-(1-x)[3Bi2O3·PbO] lead-bismuthate glasses was investigated. The glasses were investigated by infra-red spectroscopy (IR) and magnetic susceptibility measurements. The temperature dependence of the reciprocal susceptibility indicates that the erbium ions are isolated in samples with lower erbium ion content (x≤0.05) but for a higher content, a negative superexchange interaction between the magnetic erbium ions occurs. A structural model for the glasses is suggested on the basis of the IR spectral data.

Structural, Spectroscopic, and Magnetic Characterization of Cobalt(III) Oxide–Disodium Tetraborate Glasses

ABSTRACT Co2O3–Na2B4O7 glasses were prepared by melt-quenching and characterized by X-ray diffraction, density measurements, infrared spectroscopy, diffuse reflectance ultraviolet–visible spectroscopy, and magnetic measurements. Results show that addition and successive increase of cobalt oxide determines important properties of the glasses. An increase in cobalt oxide concentration converted BO4 structural units into BO3 units and led to intensification of magnetic interactions between cobalt ions. The presence of cobalt(III) in glasses was confirmed by optical spectroscopy and magnetic data.

Raman Spectroscopic Characterization of Rare Earth Ions Doped Bismuth-Based Glasses

The xReO(1−x)[3Bi2O3⋅PbO] glass systems with diferent rare earth ions (ReO = CeO2, Tb4O7) have been prepared and examined with the aim of determining their structural characteristics. Raman sprectroscopy and density measurements were used to characterize the samples. Raman spectroscopy data permitted to identify some of the structural units that built up the lead bismuthate vitreous network. Density data were used to calculate the Poisson’s ratio in terms of the Makishima‐Mackenzie model.

Magnetic Behaviour Of Some Oxide Glasses Doped With Rare Earth Ions

Magnetic susceptibility data from Er3+ and Nd3+ ions embedded in some Bi2O3 — PbO glasses are reported for the 80–300 K temperature range. The temperature dependence of reciprocal magnetic susceptibility permitted to discuss the nature of complex interactions between rare earth ions localized in lead bismuthate glass matrices.