Superconducting properties of MgB2 films electroplated to stainless steel substrates

Superconducting MgB2 films have been fabricated on stainless steel substrates by means of electroplating in a molten electrolyte composed of MgCl2, MgB2O4, NaCl, and KCl containing a fractional amount of CuCl2. Microscopic observation has revealed that the electroplated films and substrates are combined with each other through Cu-rich layers at the interfaces. Transport measurements have shown that the electroplated MgB2 films possess an upper critical field, H-c2(0), of 28 T, an irreversibility field, H-irr(0), of 13 T, and a critical current density, J(c)(5 K,0 T), of 25 000 A/cm(2), which suggests that the electroplating in molten salts is a promising alternative to the powder-in-tube method for the fabrication of MgB2 tapes. (C) 2004 American Institute of Physics.