Experimental investigation of the transverse resistivity in Nb3Sn wires through ac susceptibility

In this paper we compare two different experimental methods to estimate the transverse resistivity in superconducting NbTi and Nb3Sn multifilament wires. The first method is based on direct measurements of the resistance through micro wires bonded on the cross section of the strand. The second method exploits the physical meaning of the ac susceptibility of the multifilament wires. Both methods have been previously used: the first on Nb3Sn and NbTi strands, while the second has been applied only to NbTi wires. Here we first compare and analyze results in a NbTi system, then we extend the ac susceptibility method to Nb3Sn wires. The advantages and the limits of both techniques, when used on wires with different layouts, are analyzed. The results of the transverse resistivity obtained by using the two experimental methods are finally compared to the estimation based on a numerical approach.