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      https://www.ias.ac.in/article/fulltext/boms/039/03/0627-0632

    • Keywords

       

      Cuprate superconductors; structural studies; Raman spectroscopy.

    • Abstract

       

      We have studied for the first time the effect of Ag addition (0–15 wt%) to the superconducting system, Nd$_{1.85}$Ce$_{0.15}$CuO$_{4}$, on its crystal structure and local structural features, using synchrotron X-ray diffraction(SXRD) and Raman spectroscopy, respectively. SXRD and subsequent Rietveld refinement studies on powders of Nd$_{1.85}$Ce$_{0.15}$CuO$_4$ $+$ Ag system indicate a small but significant change in lattice parameter upon Ag addition, showing evidence for possible incorporation of Ag to the extent of $\sim$1 wt%. Raman spectroscopic studies indicate that the parent structure of Nd$_{1.85}$Ce$_{0.15}CuO$_{4}$ remains unaffected with no major local structural changes on doping with silver. However, all Raman modes show minor phonon hardening upon Ag addition, which is consistent with the unit cell volume reduction as is observed in XRD. A systematic bleaching out of the apical oxygen defect mode was also observed with increased Ag addition. Polarized Raman measurements helped to identify the asymmetric nature of the B1g Raman mode. X-ray diffraction studies on pellets of Nd$_{1.85}$Ce$_{0.15}CuO$_4$ $+$ Ag system further indicate a randomization of preferred orientation upon Ag addition. The superconductivity of the Nd$_{1.85}$Ce$_{0.15}$CuO$_4$ $+$ Ag system has been well characterized for all the compositions studied.

    • Author Affiliations

       

      N RADHIKESH RAVEENDRAN1 2 A K SINHA3 2 R RAJARAMAN1 2 M PREMILA1 E P AMALADASS1 K VINOD1 J JANAKI1 2 S KALAVATHI1 AWADHESH MANI1 2

      1. Materials Science Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102, India
      2. Homi Bhabha National Institute, Training School Complex, Mumbai 400085, India
      3. Indus Synchrotron Utilization Division, Raja Ramanna Centre for Advanced Technology, Indore 452013, India
    • Dates

       
  • Bulletin of Materials Science | News

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