On the superconducting properties of the V2Hf-base laves phase compound tapes

V2Hf-base Laves phase compound tapes were fabricated by two different processes. The first of them is the composite process in which the Laves phase layers are formed by the diffusion between the vanadium sheath and the Hf0.4Zr0.6alloy core. Critical current density Jcand upper critical field Hc2of the V/Hf0.4Zr0.6composite tape rapidly increase with decreasing temperature. At 1.7 K the Laves phase layer in the V/Hf0.4Zr0.6composite tape shows Hc2of 254 kOe and Jc(150 kOe) of 2×10⁵A/cm²which are higher than those reported for the commercially available Nb3Sn and V3Ga. The second process is the direct plastic deformation process in which the arc-melted V-Hf-Nb alloys, including the Laves phase, were cold-rolled into tapes. The V- 17at%Hf-16.3at%Nb tape shows transition temperature Tcof 9.5 K and the overall critical current density of 1×10⁴A/cm²at 100 kOe and 4.2K.