K Veera Brahmam
Articles written in Bulletin of Materials Science
Volume 28 Issue 5 August 2005 pp 411-414 Single Crystals
Single crystals of Zn1–𝑥Mn𝑥Te were prepared by vertical Bridgman crystal growth method for different concentrations of Mn. Chemical analysis and reflectivity studies were carried out for compositional and band structure properties. Microscopic variation in composition between starting and end compounds was observed from EDAX analysis. Linear dependence of fundamental absorption edge (𝐸0) as a function of Mn concentration (𝑥) was expressed in terms of a straight line fit and a shift in 𝐸0 towards higher energy was observed in reflectivity spectra of Zn1–𝑥Mn𝑥Te.
Volume 30 Issue 3 June 2007 pp 215-218 Polymers
5 mol% PVA : 𝑥 mol% Cu2+ polymer films were prepared by casting process. Thermal transitions and thermal degradation of samples with respect to copper concentration were studied by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA), respectively. Increase in glass transition temperature as a function of copper concentration shows a strong branching and steric effects in copper doped PVA complexes. Thermal degradation of films to an extent of 4–5% was found with an increase in copper content. FTIR spectrum of PVA doped Cu2+ ions indicate the presence of O–H, C–H, C=C and C–O groups.
Volume 42 | Issue 3