• K Veera Brahmam

      Articles written in Bulletin of Materials Science

    • Crystal growth and reflectivity studies of Zn1–𝑥Mn𝑥Te crystals

      K Veera Brahmam D Raja Reddy B K Reddy

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      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.

    • Thermal and IR studies on copper doped polyvinyl alcohol

      Ch Linga Raju J L Rao B C V Reddy K Veera Brahmam

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      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.

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