Temperature and field dependence of MgB2 energy gaps from tunneling spectra

Mohamed H. Badr, K. W. Ng

Research output: Contribution to journalConference articlepeer-review


We have synthesized MgB2/Pb planar junctions to study the temperature and field dependence of the superconducting energy gap of MgB2. The major peak occurs at Δ of about 2 meV, and this corresponds to a 2Δ/kBTcvalue of 1.18. While this is significantly smaller than the BCS weak coupling value, there are features in the tunneling spectra indicating the possibility of another larger gap. By fitting the dI/dV curves with a simple model, the larger gap is estimated to be about 4.5 times the smaller gap. The temperature dependence of both gaps is BCS-like, and start to open up at temperatures just below Tc (39.5 K). This confirms that these gaps are indeed bulk properties of MgB2. The junction is stable only up to a field of 3.2 T then "collapsed" into Josephson tunneling for higher fields.

Original languageEnglish
Pages (from-to)139-140
Number of pages2
JournalPhysica C: Superconductivity and its Applications
StatePublished - May 2003
Eventproceedings of the 23rd international conference on low temper - Hiroshima, Japan
Duration: Aug 20 2002Aug 27 2002

Bibliographical note

Funding Information:
This work was supported by NSF grant no. DMR9972071. The corresponding author would like to thank the Egyptian Ministry of Higher Education and Scientific Research for supporting this work as well.


  • Energy gap
  • Josephson effect
  • MgB
  • Superconductivity
  • Tunneling

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Energy Engineering and Power Technology
  • Electrical and Electronic Engineering


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