# Vortex pinning and flux flow microwave studies of coated conductors

## TL;DR

This study investigates the high-frequency electromagnetic properties of coated superconducting conductors with artificial pinning centers, revealing how these centers influence vortex dynamics and flux flow at microwave frequencies.

## Contribution

It provides the first detailed microwave frequency analysis of coated conductors with artificial pinning centers, addressing electromagnetic complexities to extract key superconductor parameters.

## Key findings

- Artificial pinning centers affect flux flow resistivity.
- Electromagnetic modeling enables accurate parameter extraction.
- Pinning constant varies with artificial pinning centers.

## Abstract

Demanding microwave applications in a magnetic field require the material optimization not only in zero-field but, more important, in the in-field flux motion dominated regime. However, the effect of artificial pinning centers (APC) remains unclear at high frequency. Moreover, in coated conductors the evaluation of the high frequency material properties is difficult due to the complicated electromagnetic problem of a thin superconducting film on a buffered metal substrate. In this paper we present an experimental study at 48 GHz of 150-200 nm YBa$_2$Cu$_3$O$_{7-x}$ coated conductors, with and without APCs, on buffered Ni-5at%W tapes. By properly addressing the electromagnetic problem of the extraction of the superconductor parameters from the measured overall surface impedance $Z$, we are able to extract and to comment on the London penetration depth, the flux flow resistivity and the pinning constant, highlighting the effect of artificial pinning centers in these samples.