PROPERTIES OF SUPERCONDUCTING NB3SI

Superconducting Nb3Si has been made by the explosive compression of the high temperature, equilibrium tetragonal T^P phase, confirming the work of Pan and his associates at Kiev. The material has a broad superconducting transition with an onset Tc18K and a mid-point16K. Tc is considerably reduced by fast neutron irradiation but can be partially recovered by annealing at 600°C. X-ray results are inconclusive but the new superconducting phase has been tentatively identified as havin the A15 structure with a lattice parameter5.12A. The upper critical field Hc2(0) is disappointingly low at 15.5-17 tesla; this is, however, not inconsistent with highly degraded A15 material. © 1979 IEEE