• Structural disorder and solid state transformations in single crystals of ZnxCd1−xS and ZnxMn1−xS

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      https://www.ias.ac.in/article/fulltext/boms/006/02/0369-0393

    • Keywords

       

      Structural disorder; single crystals; polytype structures; theoretical models

    • Abstract

       

      Single crystals of ZnxCd1−xS and ZnxMn1−xS were grown from the vapour phase at 1100°C in the rangex=0·9 to 1. X-ray characterization shows that polytypes and disordered structures occur in ZnxCd1−xS forx ≥ 0·94, whereas ZnxMn1−xS displays disordered and polytype structures in the entire rangex=0·9 to 1. It is observed that ZnxCd1−xS and ZnxMn1−xS undergo a 2H-6H solid state transformation on annealing in vacuum around 600°C. Experimental analysis of the intensity distribution along the 10·L reciprocal lattice row as recorded on a single crystal diffractometer from partially transformed crystals shows that the mechanism of the transformation cannot be explained in terms of the one-parameter models of non-random faulting reported earlier. A two-parameter theoretical model with α representing the probability of random insertion of a fault in the 2H structure and β representing the probability of the growth of the 6H nucleus, is developed both for a deformation mechanism and a layer displacement mechanism. It is found that the theoretical model of non-random deformation faulting with β ≫ α approximates the actual mechanism of transformation in these crystals.

    • Author Affiliations

       

      M T Sebastian1 P Krishna1

      1. Physics Department, Banaras Hindu University, Varanasi - 221 005, India
    • Dates

       
  • Bulletin of Materials Science | News

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