Determination of the relative influences of carbon doping and disorder on field and temperature dependent critical current density of MgB2

• Main Authors: Chen, Soo Kien, Xu, Xun, Kim, Jung Ho, Dou, Shi Xue, MacManus-Driscoll, Judith Louise
• Format: Article
• Language: English
• Published: Institute of Physics Publishing 2009
• Online Access: http://psasir.upm.edu.my/id/eprint/13965/1/Determination%20of%20the%20relative%20influences%20of%20carbon%20doping%20and%20disorder%20on%20field%20and%20temperature%20dependent%20critical%20current%20density%20of%20MgB2.pdf; http://psasir.upm.edu.my/id/eprint/13965/

SiC was mixed with Mg and B and reacted by either a one-step in situ or two-step method at 650 or 850 °C. By doing so, it was possible to determine the extent to which scattering via C doping influences the magnitude of field dependent critical current density, Jc(H), compared to pinning via generation of microstructural disorder. The one-step reaction method leads to Mg2Si formation and at the same time to more C doping of MgB2 than the two-step method. Carbon increases both the irreversibility field, Hirr, and upper critical field, Hc2 (T<28 K). However, for the temperatures (6 and 20 K) and fields (up to 7 T) studied, pinning rather than scattering overwhelmingly dominates the magnitude of the field dependent critical current density.