High Critical Current densities in Powder-in-Tube MgB2 Wires and Coils

A. SERQUIS; G. SERRANO; M. T. MALACHEVSKY; L.CIVALE; B.MAIOROV

Genova, Italia

Conferencia; 19th International Conference on Magnet Technology MT 19; 2005

  MgB2 is a promising material for making cheap and light magnets. The powder-in-tube (PIT) method is one of the best procedures for processing brittle MgB2 into superconducting wires and tapes. Previous results indicate that low level of doping with Al, C and nano SiC powders improves the critical current density (Jc) of MgB2 bulk samples. Besides, the relatively low values for the upper critical field (Bc2) reported for MgB2 in the early days were rapidly overcome by the enormous progress achieved in bulk samples and thin films in the so-called dirty limit. Therefore, the optimization of the fabrication process for MgB2 long conductors should also include methods to enhgance Bc2 and the irreversibility field (B*). In this paper we report on the fabrication and characterization of doped MgB2 wires and tapes prepared by PIT with commercial stainless steel and Ti sheaths. A series of samples have been prepared by different mechanic deformation procedures and sintered at different temperatures between 799 ºC and 950 ºC, in order to correlate their superconducting properties such as Jc, Bc2 and B* with the fabrication conditions and the doping content.