Edmund Golis

Voids in mixed-cation silicate glasses: Studies by positron annihilation lifetime and Fourier transform infrared spectroscopies ☆

PALS in comparison with FTIR studies have been applied to investigate the structure of different oxide glasses. Three components of the positron lifetime τ (τ1 para- and τ3 ortho-positronium and τ2 intermediate lifetime component) and their intensities were obtained. The results of the calculation of mean values of positron lifetimes for the investigated glasses showed the existence of a long-living component on the positron annihilation lifetime spectra. From the Tao-Eldrup formula we can estimate the size of free volume. On the basis of the measurements we can conclude that the size and fraction of free volume reaches the biggest value for the fused silica glass. The degree of network polymerisation increases void size.

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

This paper is focused on the design, fabrication and characterization of tellurite glass of composition TeO2–WO3–PbO in terms of La2O3 addition. The effect of La2O3 on the structure of the obtained glasses has been investigated by means of spectrophotometric and ellipsometric measurements in the UV-Vis-NIR spectral region and then relevant optical parameters have been calculated. The DC magnetic susceptibility study has been used to investigate the influence of lanthanum ion (La3+) on the structural and magnetic properties of the investigated glass system. Based on DTA, PALS and Raman studies, it can be stated that modification of the basic structural units with La3+ ions, namely the TeO4 trigonal bipyramid (tbp) and the TeO3 trigonal pyramid (tp), both having a lone pair of electrons occupying one of the equatorial positions, affect the magnetic properties of these glasses.

Investigations of Faraday effect in oxide glasses for optoelectronics devices

Amorphous glassy materials are of great interest on account of their possible application in optical electronics and glass fiber techniques. In this article lead-bismuth-gallium oxide glasses has been investigated. These materials are characterized by the great value of refractive index and because of absence of paramagnetic ions possess good magneto-optic properties. Measurements of the Faraday effect confirm the occurrence considerable value of the Verdet constant in the group of glasses without rare-earth elements, promising for application in magneto-optic devices.

Measurements of Defect Structures by Positron Annihilation Lifetime Spectroscopy of the Tellurite Glass 70TeO2-5XO-10P2O5-10ZnO-5PbF2 (X = Mg, Bi2, Ti) Doped with Ions of the Rare Earth Element Er3+

The objective of the study was the structural analysis of the 70TeO2-5XO-10P2O5-10ZnO-5PbF2 (X = Mg, Bi2, Ti) tellurite glasses doped with ions of the rare-earth elements Er3+, based on the PALS (positron annihilation lifetime spectroscopy) method of measuring positron lifetimes. Values of positron lifetimes and the corresponding intensities may be connected with the sizes and number of structural defects, the sizes of which range from a few angstroms to a few dozen nanometers. Experimental positron lifetime spectrum revealed existence of two positron lifetime components τ1 andτ2. Their interpretation was based on two-state positron trapping model where the physical parameters are the positron annihilation rate and positron trapping rate.

The effect of Nd3+ impurities on the magneto-optical properties of TeO2–P2O5–ZnO–LiNbO3 tellurite glass

A study of the magnetic and magneto-optical properties of tellurite glass doped with Nd3+ is discussed in this communication. These properties were determined by measuring the magnetic susceptibility and the Faraday effect. The addition of Nd3+ results in deterioration of the magneto-optical properties and changes in the structure of defects in the glass.