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      https://www.ias.ac.in/article/fulltext/boms/017/02/0153-0162

    • Keywords

       

      Flux dynamics; YBCO/Ag composite

    • Abstract

       

      DC magnetization measurements have been carried out on bulk YBCO/Ag composites with silver content up to 20wt per cent. DC fields in the range 0·5 mT to 200 mT have been used to investigate the inter- and intragranular properties at 77K. The AC susceptibility as a function of temperature at different AC fields (0·026–0·30 mT) has also been studied. Under small DC fields (≈ 4 mT), depending on the Ag content andHmax, the M-H loop shows a complicated behaviour. This behaviour can be explained on the basis of effect of strong field dependence of transport critical current, grain size and intragrain critical current densityJcgm on low-field M-H loop. The estimation of intergranular critical current densityJcjm from these loops does not remain a simple function of ΔM/d. The AC susceptibility measurements show a small increase inJc(T) with silver content under low AC fields only, consistent with the transportJc data; beyond thatJc(T) decreases. This improvement inJc(T) and transportJc with silver can be ascribed to the improved coupling between grains but not to the pinning. Also at higher field (Hmax>20 mT) the addition of Ag decreases the intragrain critical current density. The upper critical field of intergranular regionHc2j and lower critical field of intragrain regionHc1g also decrease with silver content.

    • Author Affiliations

       

      Indu Dhingra1 B K Das1 S C Kashyap1 2

      1. Materials Division, National Physical Laboratory, New Delhi - 110 012, India
      2. Centre for Materials Science and Technology, Indian Institute of Technology, New Delhi - 110 016, India
    • Dates

       
  • Bulletin of Materials Science | News

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