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      Permanent link:
      https://www.ias.ac.in/article/fulltext/boms/045/0219

    • Keywords

       

      Core/shell configuration; pressure damping; carbon nanostructures.

    • Abstract

       

      High pressure behaviour of core/shell amorphous carbon (a-C) nanostructures was studied using synchrotron X-ray diffraction (XRD) and Raman spectroscopy up to ${\sim}$25 GPa. These nanostructures having spherical a-C shells with ${\gamma}$-Fe$_2$O$_3$ nanoparticles at the core were synthesized by catalyst-assisted lamp black method. The typical size of core (${\gamma}$-Fe$_2$O$_3$)/shell (a-C) is ${\sim}$5 nm/20 nm. Comparative XRD of the core (${\gamma}$-Fe$_2$O$_3$) in opened- and closed-shell (a-C) shows that the carbon shells do not fully transmit the applied high pressure inwards, under hydrostatic conditions. Raman spectroscopy shows that the graphitic G-mode blue shifts reversibly with applied pressure with a coefficient ${\sim}$3.5 cm$^{-1}$ GPa$^{-1}$, which is ${\sim}$25 to 40% less than that for graphite and carbon nanotubes. It is suggested that a rigid and crosslinked structure of the carbon shell might be lossy for the observed pressure drop.

    • Author Affiliations

       

      G M BHALERAO1 SURAKANTI SRINIVAS REDDY1 2 BALMUKUND SHUKLA3 SOUMEE CHAKRABORTY3 V SRIHARI4 N V CHANDRA SHEKAR3

      1. UGC-DAE CSR, Kalpakkam Node, Kokilamedu 603104, India
      2. University of Madras, Chennai 600005, India
      3. Condensed Matter Physics Division, IGCAR, HBNI, Kalpakkam 603102, India
      4. High Pressure and Synchrotron Radiation Physics Division, BARC, HBNI, Mumbai 400085, India

    • Dates

       
      Published
      2 November 2022
      Manuscript received
      4 May 2022
      Accepted
      7 September 2022
      Final version published online
      2 November 2022

  • Bulletin of Materials Science | News

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