Study of NbN as superconducting material for the usage in superconducting radio frequency cavities

TL;DR

This paper investigates NbN as a superconducting material for RF cavities, focusing on its behavior under strong magnetic fields and comparing its performance to Nb3Tn, to evaluate its suitability for axion detection experiments.

Contribution

It provides experimental characterization of NbN-coated cavities in high magnetic fields, a novel application for superconducting RF cavities in axion searches.

Findings

Surface resistance increases with magnetic field

Quality factor decreases with magnetic field

Behavior similar to Nb3Tn cavities

Abstract

A new axion-haloscope is setup at the Johannes Gutenberg university of Mainz, named the Supax (a SUPerconducting AXion search) experiment. This setup is used to characterize the behaviour of a NbN coated superconducting cavity in a 2.5T strong magnetic field, at a resonance frequency of 8.4GHz. We observe an increasing surface resistance with increasing magnetic field, leading to a decreasing quality factor. The behaviour is similar to that of previously studied cavities using Nb3Tn.