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

R. A. Ribeiro; T. Ekino; T. Takasaki; T. Takabatake; J. Akimitsu

doi:10.1016/j.physc.2005.02.056

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

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

Research output: Contribution to journal › Conference article › peer-review

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 Δ_S = 2.2 ± 0.3 meV, Δ_M = 6.0 ± 1.5 meV and Δ_L = 10 meV, whereas the only clear and very reproducible gap in the wires is the small gap at Δ_S = 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 language	English
Pages (from-to)	450-453
Number of pages	4
Journal	Physica C: Superconductivity and its applications
Volume	426-431
Issue number	I
DOIs	https://doi.org/10.1016/j.physc.2005.02.056
Publication status	Published - Oct 1 2005
Externally published	Yes
Event	Proceedings of the 17th International Symposium on Superconductivity (ISS 2004) Advances in Supeconductivity - Duration: Nov 23 2004 → Nov 25 2004

Keywords

Break junction
MgB
Superconducting gap
Tunneling spectroscopy

ASJC Scopus subject areas

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

Access to Document

10.1016/j.physc.2005.02.056

Cite this

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title = "Break-junction tunneling spectra of MgB2: Influence of boron quality",

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.",

keywords = "Break junction, MgB, Superconducting gap, Tunneling spectroscopy",

author = "Ribeiro, {R. A.} and T. Ekino and T. Takasaki and T. Takabatake and J. Akimitsu",

note = "Funding Information: We would like to thank P.C. Canfield and M.A. Avila for useful discussions, and H. Miyaoka for assistance in the lab. This work was supported in part by Japan Society for the Promotion of Science (JSPS—Grant ID No. P03658) and by a Grant-in-Aid for COE research (No. 13CE2002) and for Scientific research (No. 15540346) of the Ministry of Education, Culture, Sports and Technology of Japan.; Proceedings of the 17th International Symposium on Superconductivity (ISS 2004) Advances in Supeconductivity ; Conference date: 23-11-2004 Through 25-11-2004",

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doi = "10.1016/j.physc.2005.02.056",

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TY - JOUR

T1 - Break-junction tunneling spectra of MgB2

T2 - Proceedings of the 17th International Symposium on Superconductivity (ISS 2004) Advances in Supeconductivity

AU - Ribeiro, R. A.

AU - Ekino, T.

AU - Takasaki, T.

AU - Takabatake, T.

AU - Akimitsu, J.

N1 - Funding Information: We would like to thank P.C. Canfield and M.A. Avila for useful discussions, and H. Miyaoka for assistance in the lab. This work was supported in part by Japan Society for the Promotion of Science (JSPS—Grant ID No. P03658) and by a Grant-in-Aid for COE research (No. 13CE2002) and for Scientific research (No. 15540346) of the Ministry of Education, Culture, Sports and Technology of Japan.

PY - 2005/10/1

Y1 - 2005/10/1

N2 - 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.

AB - 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.

KW - Break junction

KW - MgB

KW - Superconducting gap

KW - Tunneling spectroscopy

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