The effect of Ca substitution by Na, Mg and Yb on the structural and transport properties of Bi1.6Pb0.4Sr2Ca2-xMxCu3Oy (M = Na, Mg and Yb) (x = 0.0 and 0.2) superconducting samples have been investigated. The samples were prepared by the coprecipitation (COP) method. The samples were characterized by x-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), electrical resistivity measurement and critical current density. The critical current density (Jc) and transition temperature (Tc zero) of Na, Mg and Yb substituted with x = 0.2 were found to be lower than the pure sample. Tc zero varies between 100 K and 63 K. Mg concentration was found to give the highest Tc zero of 93 K. Tc zero gradually decreased from Mg, Yb to Na corresponding to a small change in the carrier concentration. Jc decreased with Mg, Yb and Na substitution, and it was measured to be 7.4611 A/cm2, 0.0667 A/cm2, 1.4579 A/cm2 and 1.2479 A/cm2 for pure, Na, Mg and Yb substitution, respectively at 60 K. XRD analysis showed that the decrease of the volume fraction for the 2223 phase and increase of the volume fraction for the 2212 phase with substitution of Na, Mg and Yb. The proportion of Bi-2223/Bi-2212 (%) was estimated from 78.13/21.87 for pure to 51.71/48.29 for Na substitution.

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Six samples of borotellurite glasses with system (80-x)TeO2- 10B2O3 - 10PbO - xEr2O3 (x=0.0, 0.5, 1.0, 1.5, 2.0, 2.5 mol%) have been prepared by using the conventional melt-quenching method. Some basic physical parameters such as density and molar volume were measured. The result reveals that the density and molar volume increases with the increases of mol% of Er2O3. The amorphous nature of the glass has been characterized using X-ray Diffraction (XRD) and all glasses are found to be amorphous in nature. The structure was analysed by FTIR spectroscopy. The FTIR spectra were recorded at room temperature in the frequency range from 650 to 4000  cm-1 using Attenuated Total Reflectance (ATR) method. From the IR results, the absorption bands were found to be in the range 667-669 cm-1, 710-712 cm-1, 880-887 cm-1, 981-997 cm-1 and 1190-1204 cm-1 which correspond to the stretching and bending vibrations mode. The absorption peaks around 1386-1388 cm-1 and 3741-3748 cm-1 which ascribed to the hydroxyl-metal bond and hydroxyl-hydrogen bond stretching vibration also have been observed. The FTIR results demonstrate that the existing of erbium in the composition leads to good structural properties thus creating potential for this glass in laser applications.

Glasses with chemical composition of (60-x)P2O5-25ZnO-(15+x)Li2O with 0.0 ≤ x ≤ 5.0 mol % are prepared by melt quenching technique. The physical properties, by mean of density and molar volume are determined. The amorphous nature, absorption and structural behaviour are characterized using X-ray Diffraction (XRD), Ultraviolet-visible-near infrared (UV-Vis-NIR) and Fourier transform infrared (FTIR) respectively. In this work, the glass densities are found increases in the range of 2.70 - 2.78 gcm-3 and molar volume decreases from 37.48 - 40.75 gcm-3 with respect to Li2O concentration. Meanwhile, the optical band gap energy for direct and indirect transition are found decreases from 3.074 eV to 2.525 eV and 2.699 eV to 1.670 eV respectively. The Urbach energy is varies as Li2O content increases. The refractive index of these glasses is ranging from 2.48 to 2.90. FTIR spectra exhibited seven bands which centered at 512 cm−1, 767 cm−1, 918 cm−1, 1087 cm−1, 1281 cm−1, 1627 cm−1 and 3441 cm−1 wavenumber that assigned as vibration of Zn-O, symmetric stretching vibration of P-O-P rings, asymmetric stretching vibration of P-O-P groups, asymmetric stretching of PO2-group, asymmetric stretching vibration P=O, bending vibration of water molecule and fundamental stretching of hydroxyl group.

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