Enhancement of irreversibility field in carbon-substituted MgB2 single crystals

被引：60

作者：

Ohmichi, E ^{[1
]}

Masui, T

Lee, S

Tajima, S

Osada, T

机构：

[1] Univ Tokyo, Inst Solid State Phys, Kashiwa, Chiba 2778581, Japan

[2] ISTEC, Superconduct Res Lab, Koto Ku, Tokyo 1350062, Japan

来源：

JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN | 2004年 / 73卷 / 08期

关键词：

MgB2; torque measurement; irreversibility field; carbon substitution; two-gap superconductor;

D O I：

10.1143/JPSJ.73.2065

中图分类号：

O4 [物理学];

学科分类号：

0702 ;

摘要：

We report on a detailed study of the irreversibility field H-irr of single crystals of Mg(B1-xCx)(2) (x = 0, 2, 3.5, 5 and 7.5%) in strong magnetic fields of up to 40 T. Highly sensitive torque measurements revealed that H-irr, is greatly enhanced by a factor of two (mu(0)H(irr)(0) similar or equal to 33 T with x = 5%) by carbon substitution compared with that of the pristine MgB2, owing to a reduction in in-plane coherence length. We also observed the temperature-dependent H-irr anisotropy for all carbon contents. This strongly suggests that the two-gap superconductivity of MgB2 is less influenced by a small amount of carbon substitution. We discuss these results by focusing on the impact of carrier doping and impurity scattering on a two-gap superconductor.

引用

页码：2065 / 2068

页数：4

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