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Enhancement of critical fields and current of MgB2 by co-doping

The electromagnetic properties of well-characterized iron-sheathed MgB2 wires, undoped and doped with dextrin-coated magnetite nanospheres and nanorods, have been studied in the temperature range 5–300 K and a magnetic field up to 16 T. Doping hardly affected the superconducting transition temperature and the active cross-sectional area of the wires, and increased the low temperature upper critical field, Bc2. Wire doped with nanospheres also showed enhanced irreversibility field, Birr, and low temperature (T ≤ 15 K) critical current density. Magnetization measurements generally confirm the transport results and indicate an enhancement of flux pinning in nanosphere doped wire for T ≤ 20 K. Annealing of wire doped with nanorods at higher temperature (750 ° C) enhanced its critical fields, as expected for co-doping.

MgB2 wires ; co-doping ; magnetic nanoparticle ; flux pinning

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