Superconducting gap in polycrystalline MgB2 studied by electron tunneling

被引：17

作者：

Takasaki, T

Ekino, T ^{[1
]}

Muranaka, T

Fujii, H

Akimitsu, J

机构：

[1] Hiroshima Univ, Fac Integrated Arts & Sci, Higashihiroshima 7398521, Japan

[2] Aoyama Gakuin Univ, Dept Phys, Tokyo, Tokyo 1578572, Japan

来源：

PHYSICA C-SUPERCONDUCTIVITY AND ITS APPLICATIONS | 2002年 / 378卷

关键词：

tunneling spectroscopy; break junction; MgB2;

D O I：

10.1016/S0921-4534(02)01418-1

中图分类号：

O59 [应用物理学];

学科分类号：

摘要：

Electron-tunneling measurements on the new superconductor MgB2 with T-c = 39 K have been carried out using a break-junction technique. The measurements reveal the largest gap value of 2Delta = 17-19 meV at 4.2 K. This value leads to the ratio 2Delta/k(B)T(c) = 5-5.6, indicating the strong-coupling superconductivity. We have also observed the reproducible gap values of 2Delta congruent to 4-4.5 meV and 7-9 meV. The smallest gap exists even beyond 30 K. We will discuss the implication of the data. (C) 2002 Published by Elsevier Science B.V.

引用

收藏

页码：229 / 233

页数：5

相关论文

共 16 条

[1] Boron isotope effect in superconducting MgB2 [J].

Bud'ko, SL ;

Lapertot, G ;

Petrovic, C ;

Cunningham, CE ;

Anderson, N ;

Canfield, PC .

PHYSICAL REVIEW LETTERS, 2001, 86 (09) :1877-1880

[2] TUNNELING EVIDENCE FOR THE QUASI-PARTICLE GAP IN KONDO SEMICONDUCTORS CENISN AND CERHSB [J].

EKINO, T ;

TAKABATAKE, T ;

TANAKA, H ;

FUJII, H .

PHYSICAL REVIEW LETTERS, 1995, 75 (23) :4262-4265

[3] Tunneling spectroscopy of the normal-state gap in (Bi, Ph)2Sr2Ca2Cu3O10+δ -: art. no. 092510 [J].

Ekino, T ;

Hashimoto, S ;

Takasaki, T ;

Fujii, H .

PHYSICAL REVIEW B, 2001, 64 (09)

[4] DETERMINATION OF ENERGY GAP OF A SUPERCONDUCTING TIN-LEAD SANDWICH BY ELECTRON TUNNELING [J].

GILABERT, A ;

ROMAGNAN, JP ;

GUYON, E .

SOLID STATE COMMUNICATIONS, 1971, 9 (15) :1295-&

[5] Strong coupling and double-gap density of states in superconducting MgB2 [J].

Giubileo, F ;

Roditchev, D ;

Sacks, W ;

Lamy, R ;

Klein, J .

EUROPHYSICS LETTERS, 2002, 58 (05) :764-770

[6]

Karapetrov G, 2001, PHYS REV LETT, V86, P4374, DOI 10.1103/PhysRevLett.86.4374

[7] Direct observation of nanometer-scale Mg- and B-oxide phases at grain boundaries in MgB2 [J].

Klie, RF ;

Idrobo, JC ;

Browning, ND ;

Regan, KA ;

Rogado, NS ;

Cava, RJ .

APPLIED PHYSICS LETTERS, 2001, 79 (12) :1837-1839

[8]

KOTEGAWA H, 2001, PHYS REV LETT, V87

[9] Beyond Eliashberg superconductivity in MgB2:: Anharmonicity, two-phonon scattering, and multiple gaps -: art. no. 087005 [J].

Liu, AY ;

Mazin, II ;

Kortus, J .

PHYSICAL REVIEW LETTERS, 2001, 87 (08) :87005-1

[10] Superconductivity at 39 K in magnesium diboride [J].

Nagamatsu, J ;

Nakagawa, N ;

Muranaka, T ;

Zenitani, Y ;

Akimitsu, J .

NATURE, 2001, 410 (6824) :63-64