Break-junction tunneling spectra of MgB2: Influence of boron quality

R. A. Ribeiro, T. Ekino, T. Takasaki, T. Takabatake, Jun Akimitsu

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

Tunneling spectra of a superconductor-insulator-superconductor (SIS) junction formed by the break-junction technique have been carried out for two different boron quality MgB2 samples. One is a polycrystalline MgB2 pellet (RRR ≈ 4) and the other is a high purity MgB 2 wire (RRR ≈ 25) of approximately 150 μm in diameter. Both samples exhibit a multiple-gap feature, which can be expressed by the correlated two-gap model. From the conductance fitting at 4.2 K, the pellet gap parameters are ΔS = 2.2 ± 0.3 meV, ΔM = 6.0 ± 1.5 meV and ΔL = 10 meV, whereas the only clear and very reproducible gap in the wires is the small gap at ΔS = 2.5 ± 0.1 meV. The wires show almost constant values for the fitting parameters of the two-gap model, in contrast with the pellets that show a large variation.

Original languageEnglish
Pages (from-to)450-453
Number of pages4
JournalPhysica C: Superconductivity and its Applications
Volume426-431
Issue numberI
DOIs
Publication statusPublished - Oct 1 2005
Externally publishedYes

Fingerprint

Boron
boron
Wire
Superconducting materials
pellets
wire
SIS (superconductors)
purity

Keywords

  • Break junction
  • MgB
  • Superconducting gap
  • Tunneling spectroscopy

ASJC Scopus subject areas

  • Condensed Matter Physics

Cite this

Break-junction tunneling spectra of MgB2 : Influence of boron quality. / Ribeiro, R. A.; Ekino, T.; Takasaki, T.; Takabatake, T.; Akimitsu, Jun.

In: Physica C: Superconductivity and its Applications, Vol. 426-431, No. I, 01.10.2005, p. 450-453.

Research output: Contribution to journalArticle

Ribeiro, R. A. ; Ekino, T. ; Takasaki, T. ; Takabatake, T. ; Akimitsu, Jun. / Break-junction tunneling spectra of MgB2 : Influence of boron quality. In: Physica C: Superconductivity and its Applications. 2005 ; Vol. 426-431, No. I. pp. 450-453.
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