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Eleven glass compositions were prepared by melt and quench method with progressive substitution of SrO for PbO (0 ≤ x ≤ 1•0) with a step-wise increment of 0•10 in the glass [(Pb x Sr 1−x)OTiO 2 ]-[(2SiO 2 B 2 O 3)]-[BaO•K 2 O]•Nb 2 O 5 (mol percentage) system. The infrared spectra (IR) of various glass compositions in the above mentioned glass system was recorded over a continuous spectral range 400-4000 cm −1 to study their different oxides structure systematically. Differential thermal analysis (DTA) was recorded from room temperature (∼27 • C) to 1400 • C employing a heating rate of 10 • C/min to determine glass transition temperature, T g and crystallization temperature, T c. The melting temperature, T m , of these glass compositions was found to be in the range 597-1060 • C depending on the composition under normal atmospheric conditions. T g and T m of glasses were found to increase with increasing SrO content. X-ray diffraction analysis of these glass-ceramic samples shows that major crystalline phase of the glass-ceramic sample with x ≤ 0•5 was found to have cubic structure similar to SrTiO 3 ceramic. Scanning electron microscopy has been carried out to see the surface morphology of the crystallites dispersed in the glassy matrix. Keywords. (PbSr)TiO 3 borosilicate glasses; infrared spectroscopy; DTA; XRD and SEM.

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The systematic study on structural properties of Ba-substituted La0.9Sr0.1Al0.9Mg0.1O3–δ and its correlation with conductivity was carried out. X-ray diffraction patterns indicated that the system formed a single phase composition up to 3% of Ba double substitution at the La-site. Energy dispersive X-ray spectroscopy and XPS results confirmed elemental compositions and revealed the maximum deficiency in oxygen for the 3% Ba-substituted sample. Dense grain formation is observed in SEM images, complementing higher density of these samples (>93%). Electrical conductivity was found to be in correlation with a new structural parameter of the critical triangle of (La/Sr/Ba)-Al/Mg-(La/Sr/Ba). The value of conductivity increased by an order of 2 in a substituted sample as compared to pure LaAlO3. The activation energy can be correlated with the area of the critical triangle of (La/Sr/Ba)-Al/Mg-(La/Sr/Ba). The migration path for ionic conduction of the oxygen ion was mapped out using the correlation of bulk conductivity with the A-A-B angle (β) and dc conductivity with the A-B-A angle (α).