# Surface impedance measurements on Nb$_{3}$Sn at high magnetic fields

## TL;DR

This study measures the surface impedance of Nb$_{3}$Sn at 15 GHz in high magnetic fields up to 12 T, revealing its potential for RF applications due to high depinning frequencies and strong vortex pinning.

## Contribution

First surface impedance measurements of Nb$_{3}$Sn at high magnetic fields, providing new insights into its vortex dynamics and suitability for RF technology.

## Key findings

- Measured $
u_p$ in Nb$_{3}$Sn is several times higher than in pure Nb.
- Nb$_{3}$Sn exhibits strong vortex pinning at high frequencies.
- Results suggest Nb$_{3}$Sn's potential for high-field RF applications.

## Abstract

Nb$_{3}$Sn is a superconductor of great relevance for perspective RF applications. We present for the first time surface impedance $Z_s$ 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. $Z_s$ 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 $Z_s$ with the aim of extracting interesting data about pinning in Nb$_{3}$Sn at high frequencies. From $Z_s$ we extract the vortex motion complex resistivity to obtain the $r$-parameter and the depinning frequency $\nu_p$ in high magnetic fields. The comparison of the results with the literature shows that the measured $\nu_p$ 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.