Surface Impedance Measurements on Nb$_{3}$Sn in High Magnetic Fields

Nb
₃
Sn is a superconductor of great relevance for perspective radiofrequency (RF) applications. We present for the first time surface impedance (Z9) measurements at 15 GHz and low-RF field amplitude on Nb
₃
Sn in high magnetic fields up to 12 T, with the aim of increasing the knowledge of Nb
₃
Sn behavior in such conditions. Z
₉
is a fundamental material parameter that directly gives useful information about the dissipative and reactive phenomena when the superconductor is subjected to high-frequency excitations. Therefore, we present an analysis of the measured Z
₉
with the aim of extracting interesting data about pinning in Nb
₃
Sn at high frequencies. From Z
₉
, we extract the vortex motion complex resistivity to obtain the r-parameter and the depinning frequency up in high magnetic fields. The comparison of the results with the literature shows that the measured up on bulk Nb
₃
Sn is several times greater than that of pure Nb. This demonstrates how Nb
₃
Sn can be a good candidate for RF technological applications, also in high magnetic fields.