Effect of carbon-doping in bulk superconducting MgB2 samples

M. Paranthaman; J. R. Thompson; D. K. Christen

doi:10.1016/S0921-4534(01)00424-5

Effect of carbon-doping in bulk superconducting MgB₂ samples

M. Paranthaman, J. R. Thompson, D. K. Christen

Nanomaterials Chemistry Group

Research output: Contribution to journal › Article › peer-review

89 Scopus citations

Abstract

Bulk superconducting samples of MgB₂ were prepared by solid state reaction of stoichiometric quantities of Mg turnings and B in a sealed Ta cylinder at 890°C for 2 h. The "as-synthesized" MgB₂ samples had a T_c of 39 K, as defined as the onset of diamagnetism. The crystal symmetry was found to be hexagonal with lattice parameters, a = 3.0856 Å, and c = 3.5199 Å, similar to the literature values. To study the effect of carbon-doping in MgB₂, various C-containing samples of x varying from 0 to 1.00 in MgB_2-xC_x were prepared. Magnetic characterizations indicate that the T_c onset is same for pure and C-doped samples for x = 0.05 and 0.10. However, the shielding signal decreased monotonically with C content, apparently due to the presence of carbon on the grain boundaries that isolates grains and prevents flow of supercurrents on the perimeter.

Original language	English
Pages (from-to)	1-5
Number of pages	5
Journal	Physica C: Superconductivity and its Applications
Volume	355
Issue number	1-2
DOIs	https://doi.org/10.1016/S0921-4534(01)00424-5
State	Published - Jun 1 2001

Funding

This work was supported by the US Department of Energy, Division of Materials Sciences, Office of Science, Office of Power Technologies-Superconductivity Program, Office of Energy Efficiency and Renewable Energy. The research was performed at the Oak Ridge National Laboratory, managed by U.T.-Battelle, LLC for the USDOE under contract DE-AC05-00OR22725.

Keywords

Bulk samples
Carbon-doping
Meissner state magnetization
MgB superconductors
X-ray studies

Access to Document

10.1016/S0921-4534(01)00424-5

Cite this

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title = "Effect of carbon-doping in bulk superconducting MgB2 samples",

abstract = "Bulk superconducting samples of MgB2 were prepared by solid state reaction of stoichiometric quantities of Mg turnings and B in a sealed Ta cylinder at 890°C for 2 h. The {"}as-synthesized{"} MgB2 samples had a Tc of 39 K, as defined as the onset of diamagnetism. The crystal symmetry was found to be hexagonal with lattice parameters, a = 3.0856 {\AA}, and c = 3.5199 {\AA}, similar to the literature values. To study the effect of carbon-doping in MgB2, various C-containing samples of x varying from 0 to 1.00 in MgB2-xCx were prepared. Magnetic characterizations indicate that the Tc onset is same for pure and C-doped samples for x = 0.05 and 0.10. However, the shielding signal decreased monotonically with C content, apparently due to the presence of carbon on the grain boundaries that isolates grains and prevents flow of supercurrents on the perimeter.",

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AU - Thompson, J. R.

AU - Christen, D. K.

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N2 - Bulk superconducting samples of MgB2 were prepared by solid state reaction of stoichiometric quantities of Mg turnings and B in a sealed Ta cylinder at 890°C for 2 h. The "as-synthesized" MgB2 samples had a Tc of 39 K, as defined as the onset of diamagnetism. The crystal symmetry was found to be hexagonal with lattice parameters, a = 3.0856 Å, and c = 3.5199 Å, similar to the literature values. To study the effect of carbon-doping in MgB2, various C-containing samples of x varying from 0 to 1.00 in MgB2-xCx were prepared. Magnetic characterizations indicate that the Tc onset is same for pure and C-doped samples for x = 0.05 and 0.10. However, the shielding signal decreased monotonically with C content, apparently due to the presence of carbon on the grain boundaries that isolates grains and prevents flow of supercurrents on the perimeter.

AB - Bulk superconducting samples of MgB2 were prepared by solid state reaction of stoichiometric quantities of Mg turnings and B in a sealed Ta cylinder at 890°C for 2 h. The "as-synthesized" MgB2 samples had a Tc of 39 K, as defined as the onset of diamagnetism. The crystal symmetry was found to be hexagonal with lattice parameters, a = 3.0856 Å, and c = 3.5199 Å, similar to the literature values. To study the effect of carbon-doping in MgB2, various C-containing samples of x varying from 0 to 1.00 in MgB2-xCx were prepared. Magnetic characterizations indicate that the Tc onset is same for pure and C-doped samples for x = 0.05 and 0.10. However, the shielding signal decreased monotonically with C content, apparently due to the presence of carbon on the grain boundaries that isolates grains and prevents flow of supercurrents on the perimeter.

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