Significant enhancement of irreversibility field in clean-limit bulk MgB2

Abstract

Low resistivity ("clean") MgB2 bulk samples annealed in Mg vapor show an increase in upper critical field Hc2(T) and irreversibility field Hirr(T) by a factor of 2 in both transport and magnetic measurements. The best sample displayed Hirr above 14 T at 4.2 K and 6 T at 20 K. These changes were accompanied by an increase of the 40 K resistivity from 1.0 to 18 microohm-cm and a lowering of the resistivity ratio from 15 to 3, while the critical temperature Tc decreased by only 1-2 K. These results point the way to make prepare MgB2 attractive for magnet applications.

arXiv comment3 pages, 4 figures, submitted to Applied Physics Letters

References in corpus (9)

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• Properties of superconducting MgB_2 wires: "in-situ" versus "ex-situ" reaction technique
• Thermally-activated current transport in MgB_2 films
• Temperature dependence of trapped magnetic field in MgB2 bulk superconductor
• Anisotropic Connectivity and its Influence on Critical Current Densities, Irreversibility Fields, and Flux Creep in In-Situ-Processed MgB2 Strands
• Sonochemical Modification of the Superconducting Properties of MgB2
• Upper Critical Fields up to 60T in Dirty Magnesium Diboride Thin Films
• Magnetic field dependence of vortex activation energy: a comparison between MgB2, NbSe2 and Bi2Sr2Ca2Cu3O10 superconductors
• Improved Current Densities in MgB2 By Liquid-Assisted Sintering