Investigation of the structure of gallium oxide glasses by means of positron lifetime measurements

Abstract

Positron lifetime spectroscopy PALS has been applied to the investigation of the structure of gallium oxide glasses. Three components of the positron lifetime τ τ τ τ (τ τ τ τ 1 para-and τ τ τ τ 3 ortho-positronium and τ τ τ τ 2 average living component) and its intensities I were obtained. The analysis shows that the obtained lifetime components correspond to the occurrence of free volume holes (τ τ τ τ 1 and τ τ τ τ 3) and positron trapping in vacancy-type defects (τ τ τ τ 2). From the Tao-Eldrup formula we can estimate the size of the free volume. The percentage of intensities of the individual components of the positron lifetime shows that it is strongly dominated by vacancy-type defects.

Influence of lanthanum on structural and magneto-optic properties of diamagnetic glasses of the TeO2–WO3–PbO system

“…The positive inuence of lanthanum oxide addition on the thermal stability of glasses of the TeO 2 -WO 3 -PbO-La 2 O 3 system has been conrmed by earlier papers. 8,9 To improve the thermal stability of very well known glass system TeO 2 -ZnO-Na 2 O, [10][11][12] the heavy metal oxides such as BaO and La 2 O 3 have been added. 13 La 3+ -ion containing glasses are reported as excellent laser materials and presence of these ions in the glass host greatly improve the nonlinear optical properties of glasses.…”

The effect of Nd3+impurities on the magneto-optical properties of TeO2–P2O5–ZnO–LiNbO3tellurite glass

“…Doping the pure matrix of the S1 tellurite glass with Nd 3+ neodymium ions did not result in the expected improvement in the magneto-optical properties of the examined glass, and consequently, in an increase of the Verdet constant value for the S4 glass, as was the case in the tellurite glasses doped with lanthanum oxide. 10,16 In spite of the increased value of the magnetic susceptibility due to the introduction of Nd 3+ neodymium ions into the glass matrix, a substantial drop of the Verdet constant value was observed, as is shown in Fig. 2 and 3.…”

“…The inuence of neodymium ions on the magneto-optical properties is of a completely different nature than the one observed for doping tellurite glasses with lanthanum oxide, where a signicant increase in the value of the Verdet constant was observed. 10,16 Doping the examined tellurite glasses with neodymium ions in order to increase their magneto-optical properties did not bring expected results. Introducing neodymium ions characterised by a ferromagnetic inuence into a tellurite glass matrix showing poor paramagnetic properties, could result in a reorganization of the magnetic domains in the examined material.…”

“…Interesting results involving the improvement of the magneto-optical properties in tellurite glasses by doping them with lanthanum La 3+ have been presented in papers. 10,16 An attempt to obtain similar results for a different tellurite glass matrix with the use of Nd 3+ ions has been made in this paper. The usefulness of this study results from the fact that the glasses doped with rare earth elements have become competitive in their application, in comparison to other materials, due to their low price and the simplicity of the processes of manufacturing and moulding.…”

“…On account of their very interesting physical and chemical properties, [10][11][12][13][14] including a high refractive index exceeding a value of 2, special tellurite glasses constitute a very promising material for building magneto-optical devices. 8 The basic unit building the structure of a tellurite glass is the trigonal bipyramid of TeO 4 .…”