# Magnetoresistance in copper at high frequency and high magnetic fields

## TL;DR

This study measures the magnetoresistance of copper at 12.9 GHz and high magnetic fields up to 15 T at liquid helium temperatures, providing novel insights relevant for high-frequency axion search experiments.

## Contribution

First measurement of high-frequency magnetoresistance in copper at magnetic fields above 10 T, relevant for cavity-based axion detection.

## Key findings

- Consistent with anomalous skin and size effects
- First high-frequency (>10 GHz) magnetoresistance measurement in high magnetic fields (>10 T)
- Data supports understanding of cavity properties in extreme conditions

## Abstract

In halo dark matter axion search experiments, cylindrical microwave cavities are typically employed to detect signals from the axion-photon conversion. To enhance the conversion power and reduce the noise level, cavities are placed in strong solenoid magnetic fields at sufficiently low temperatures. Exploring high mass regions in cavity-based axion search experiments requires high frequency microwave cavities and thus understanding cavity properties at high frequencies in extreme conditions is deemed necessary. We present a study of the magnetoresistance of copper using a cavity with a resonant frequency of 12.9 GHz at the liquid helium temperature in magnetic fields up to 15 T utilizing a second generation high temperature superconducting magnet. The observations are interpreted to be consistent with the anomalous skin effect and size effect. This is the first measurement of magnetoresistance at a high frequency (> 10 GHz) in high magnetic fields (> 10 T).