Influence of heat treatment on the critical current density of MgB2 bulk sintered in vacuum and flowing Ar atmosphere

Three types of boron precursor powders with a purity ranging from 90% to 99% from Alfa Aesar were investigated. A common magnesium powder was mixed with each type of the boron powders in a stoichiometric MgB2 composition. The samples were heat-treated at 700 deg C or 850 deg C for 30 min in vacuum o...

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Bibliographic Details
Published in:Physica. C, Superconductivity Superconductivity, 2008-09, Vol.468 (15-20), p.1366-1368
Main Authors: TAN, K. S, KIM, N.-K, KIM, Y.-J, JUN, B.-H, KIM, C.-J
Format: Article
Language:English
Subjects:
Condensed matter: electronic structure, electrical, magnetic, and optical properties
Critical currents
Exact sciences and technology
Physics
Properties of type I and type II superconductors
Superconductivity
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Summary:Three types of boron precursor powders with a purity ranging from 90% to 99% from Alfa Aesar were investigated. A common magnesium powder was mixed with each type of the boron powders in a stoichiometric MgB2 composition. The samples were heat-treated at 700 deg C or 850 deg C for 30 min in vacuum or in flowing Ar atmosphere. The results show the samples annealed in vacuum have a higher Jc when annealed at a lower temperature. On the contrary, samples annealed in the flowing Ar gas showed a higher Jc when annealed at a higher temperature. At a particular annealing temperature, samples annealed in the Ar atmosphere always showed a higher Jc compared to vacuum annealing. One of the reasons is attributed to a greater magnesium loss when annealed in vacuum and at high temperatures.
ISSN:0921-4534
1873-2143
DOI:10.1016/j.physc.2008.05.057