Tunneling measurements of superconducting NbB2

Toshikazu Ekino; Tomoaki Takasaki; Hiroyuki Takagiwa; Jun Akimitsu; Hironobu Fujii

doi:10.1016/j.physc.2004.03.149

Tunneling measurements of superconducting NbB₂

Toshikazu Ekino, Tomoaki Takasaki, Hiroyuki Takagiwa, Jun Akimitsu, Hironobu Fujii

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

4 Citations (Scopus)

Abstract

We have measured superconducting tunneling spectra of NbB₂. This compound is isostructural to the high-T_c superconductor MgB ₂. The most representative spectra at 4.2 K exhibit intensive gap-edge peaks at ±2.2-2.6 mV ( = ±2Δ/e) for the superconductor-insulator-superconductor (SIS) break junction. Upon warming, the gap feature disappears at T_c = 6.5-7 K. This leads to the gap ratio 2Δ(0)/k_BT_c = 4.3-4.5 with the extrapolated Δ(0) using the BCS prediction. The present result demonstrates that NbB₂ is a strong-coupling superconductor with the gap ratio comparable to that for MgB₂.

Original language	English
Pages (from-to)	828-829
Number of pages	2
Journal	Physica C: Superconductivity and its applications
Volume	408-410
Issue number	1-4
DOIs	https://doi.org/10.1016/j.physc.2004.03.149
Publication status	Published - Aug 2004
Externally published	Yes
Event	Proceedings of the International Conference on Materials - Rio de Janeiro, Brazil Duration: May 25 2003 → May 30 2003

Keywords

AlB-type structure
Break junction
Electron tunneling
NbB
Superconducting gap

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.2004.03.149

Cite this

@article{5b32d972f01e4a9f8054fa25917b7b6b,

title = "Tunneling measurements of superconducting NbB2",

abstract = "We have measured superconducting tunneling spectra of NbB2. This compound is isostructural to the high-Tc superconductor MgB 2. The most representative spectra at 4.2 K exhibit intensive gap-edge peaks at ±2.2-2.6 mV ( = ±2Δ/e) for the superconductor-insulator-superconductor (SIS) break junction. Upon warming, the gap feature disappears at Tc = 6.5-7 K. This leads to the gap ratio 2Δ(0)/kBTc = 4.3-4.5 with the extrapolated Δ(0) using the BCS prediction. The present result demonstrates that NbB2 is a strong-coupling superconductor with the gap ratio comparable to that for MgB2.",

keywords = "AlB-type structure, Break junction, Electron tunneling, NbB, Superconducting gap",

author = "Toshikazu Ekino and Tomoaki Takasaki and Hiroyuki Takagiwa and Jun Akimitsu and Hironobu Fujii",

note = "Funding Information: This work is supported in part by a Grant-in-Aid for COE research (No. 13CE2002) of the Ministry of Education, Culture, Sports, Science and Technology of Japan.; Proceedings of the International Conference on Materials ; Conference date: 25-05-2003 Through 30-05-2003",

year = "2004",

month = aug,

doi = "10.1016/j.physc.2004.03.149",

language = "English",

volume = "408-410",

pages = "828--829",

journal = "Physica C: Superconductivity and its Applications",

issn = "0921-4534",

publisher = "Elsevier",

number = "1-4",

}

TY - JOUR

T1 - Tunneling measurements of superconducting NbB2

AU - Ekino, Toshikazu

AU - Takasaki, Tomoaki

AU - Takagiwa, Hiroyuki

AU - Akimitsu, Jun

AU - Fujii, Hironobu

N1 - Funding Information: This work is supported in part by a Grant-in-Aid for COE research (No. 13CE2002) of the Ministry of Education, Culture, Sports, Science and Technology of Japan.

PY - 2004/8

Y1 - 2004/8

N2 - We have measured superconducting tunneling spectra of NbB2. This compound is isostructural to the high-Tc superconductor MgB 2. The most representative spectra at 4.2 K exhibit intensive gap-edge peaks at ±2.2-2.6 mV ( = ±2Δ/e) for the superconductor-insulator-superconductor (SIS) break junction. Upon warming, the gap feature disappears at Tc = 6.5-7 K. This leads to the gap ratio 2Δ(0)/kBTc = 4.3-4.5 with the extrapolated Δ(0) using the BCS prediction. The present result demonstrates that NbB2 is a strong-coupling superconductor with the gap ratio comparable to that for MgB2.

AB - We have measured superconducting tunneling spectra of NbB2. This compound is isostructural to the high-Tc superconductor MgB 2. The most representative spectra at 4.2 K exhibit intensive gap-edge peaks at ±2.2-2.6 mV ( = ±2Δ/e) for the superconductor-insulator-superconductor (SIS) break junction. Upon warming, the gap feature disappears at Tc = 6.5-7 K. This leads to the gap ratio 2Δ(0)/kBTc = 4.3-4.5 with the extrapolated Δ(0) using the BCS prediction. The present result demonstrates that NbB2 is a strong-coupling superconductor with the gap ratio comparable to that for MgB2.

KW - AlB-type structure

KW - Break junction

KW - Electron tunneling

KW - NbB

KW - Superconducting gap

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U2 - 10.1016/j.physc.2004.03.149

DO - 10.1016/j.physc.2004.03.149

M3 - Conference article

AN - SCOPUS:4444384172

SN - 0921-4534

VL - 408-410

SP - 828

EP - 829

JO - Physica C: Superconductivity and its Applications

JF - Physica C: Superconductivity and its Applications

IS - 1-4

T2 - Proceedings of the International Conference on Materials

Y2 - 25 May 2003 through 30 May 2003

ER -