Observing the suppression of superconductivity in RbEuFe$_4$As$_4$ by correlated magnetic fluctuations

TL;DR

This study uses magnetic imaging to show how magnetic fluctuations suppress superconductivity in RbEuFe4As4, revealing strong interactions between magnetic and superconducting layers.

Contribution

It provides the first quantitative imaging evidence of superconductivity suppression by magnetic fluctuations in RbEuFe4As4, aligning with theoretical models.

Findings

Superfluid density decreases near magnetic ordering temperature.

Magnetic fluctuations correlate with suppression of superconductivity.

Strong exchange interaction between magnetic and superconducting layers.

Abstract

In this letter, we describe quantitative magnetic imaging of superconducting vortices in RbEuFe$_4$As$_4$ in order to investigate the unique interplay between the magnetic and superconducting sublattices. Our scanning Hall microscopy data reveal a pronounced suppression of the superfluid density near the magnetic ordering temperature in good qualitative agreement with a recently-developed model describing the suppression of superconductivity by correlated magnetic fluctuations. These results indicate a pronounced exchange interaction between the superconducting and magnetic subsystems in RbEuFe\textsubscript{4}As\textsubscript{4} with important implications for future investigations of physical phenomena arising from the interplay between them.