Improved superconducting properties in nanocrystalline bulk MgB2

被引：219

作者：

Gümbel, A ^{[1
]}

Eckert, J ^{[1
]}

Fuchs, G ^{[1
]}

Nenkov, K ^{[1
]}

Müller, KH ^{[1
]}

Schultz, L ^{[1
]}

机构：

[1] IFW Dresden, Inst Met Mat, D-01069 Dresden, Germany

来源：

APPLIED PHYSICS LETTERS | 2002年 / 80卷 / 15期

关键词：

Mechanical alloying - Grain boundaries - Nanocrystals - Magnesium compounds;

D O I：

10.1063/1.1469654

中图分类号：

O59 [应用物理学];

学科分类号：

摘要：

High density nanocrystalline MgB2 bulk superconductors with distinctly improved pinning were prepared by mechanical alloying of Mg and B powders at ambient temperatures followed by hot pressing. The nanocrystalline samples reveal high j(c)=10(5) A/cm(2) at 20 K and 1 T together with an irreversibility line strongly shifted towards higher fields resulting in H-irr(T)similar to0.8 H-c2(T), whereas typically H-irr(T)similar to0.5 H-c2(T) is observed for untextured bulk samples. These values exceed those of all other reported bulk samples and are in the range of values for thin films. The improved pinning of this material, which mainly consists of spherical grains about 40-100 nm in size, is attributed to the large number of grain boundaries in the nanocrystalline state. (C) 2002 American Institute of Physics.

引用

页码：2725 / 2727

页数：3

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