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      https://www.ias.ac.in/article/fulltext/pram/058/02/0361-0369

    • Keywords

       

      Microwave absorption; superconductivity

    • Abstract

       

      Non-resonant microwave absorption (NRMA) studies of superconducting MgB2 and a sample containing ∼10% by weight of MgO in MgB2 are reported. The NRMA results indicate near absence of intergranular weak links in the pure MgB2 sample. A linear temperature dependence of the lower critical field Hc1 is observed indicating a non-s wave superconductivity. However, the phase reversal of the NRMA signal which could suggest d wave symmetry is also not observed. In the MgB2 + MgO sample, much larger low field dependent absorption is observed indicating the presence of intergranular weak links. The hysteretic behavior of NRMA is compared and contrasted in the two samples. In the pure MgB2 sample, a large hysteresis is observed between the forward and the reverse scans of the magnetic field indicating strong pinning of flux lines. This hysteresis saturates a few degrees below Tc while in the MgB2 + MgO sample, a much slower increase of hysteresis with decreasing temperature is observed, a signature of weaker pinning.

    • Author Affiliations

       

      Janhavi P Joshi1 Subhasis Sarangi1 AK Sood1 Dilip Pal2 SV Bhat1

      1. Department of Physics, Indian Institute of Science, Bangalore - 560 012, India
      2. Tata Institute of Fundamental Research, Mumbai - 400 005, India
    • Dates

       
  • Pramana – Journal of Physics | News

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