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Significant enhancement of irreversibility field in clean-limit bulk MgB2

V. Braccini·L. D. Cooley·S. Patnaik·P. Manfrinetti·A. Palenzona·A. S. Siri·D. C. Larbalestier
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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.

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V. Braccini, L. D. Cooley, S. Patnaik, P. Manfrinetti, A. Palenzona, A. S. Siri, D. C. Larbalestier. 2002-08-12. Significant enhancement of irreversibility field in clean-limit bulk MgB2. https://doi.org/10.1063/1.1528289

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