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Synthesis and characterization of excess magnesium MgB2 superconductor under inert carbon environment

โœ Scribed by B.B. Sinha; M.B. Kadam; M. Mudgel; V.P.S. Awana; Hari Kishan; S.H. Pawar


Book ID
104084149
Publisher
Elsevier Science
Year
2010
Tongue
English
Weight
921 KB
Volume
470
Category
Article
ISSN
0921-4534

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โœฆ Synopsis


The structural, transport and magnetic properties of MgB 2 superconductor heavily blended with Mg is studied. The samples are synthesized with a new approach in both, pressed carbon environment and in flowing argon. The excess magnesium used is observed to play dual role: one being the prevention of Mg losses during the synthesis process and hence maintaining the stoichiometry of MgB 2 phase, and second being the formation of Mg milieu probably all around the MgB 2 grains to give a dense structure. Excess Mg also improves the grain connectivity by going into the pores and there by minimizing the insulating junctions. The residual resistivity of the sample is observed to decrease from 57.02 lX cm to 10.042 lX cm as it is progressively filled with superconductor-normal-superconductor (SNS) type junctions amongst the grains by the virtue of increased magnesium content. The synthesized samples devoid of porosity show the superconducting transition, T c in the range of 39-34 K as of clean MgB 2 samples, though overloaded with Mg. The excess Mg resulted in enhanced critical current density, J c from 6.8 ร‚ 10 3 A cm ร€2 to 5.9 ร‚ 10 4 A cm ร€2 at 20 K and 10 kOe, with reasonable decrease in the superconducting transition. Thus our samples being overloaded with Mg impart mechanical strength and competitive superconducting properties, which forms a part of interest.


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