Interplay between superconductivity and magnetism in K-doped EuFe2As2

TL;DR

This study investigates how superconductivity interacts with magnetic order in 50% K-doped EuFe2As2, revealing suppression of Fe magnetic order and coexistence of Eu magnetic fluctuations with superconductivity.

Contribution

It provides experimental evidence showing the suppression of Fe magnetic order and the coexistence of Eu magnetic fluctuations with superconductivity in K-doped EuFe2As2.

Findings

Superconductivity appears below 33 K in K-doped EuFe2As2.

Fe magnetic order is suppressed in the doped sample.

Eu magnetic moments exhibit short-range order coexisting with superconductivity.

Abstract

Superconductivity is found in 50% K-doped EuFe2As2 sample below 33 K. Our results of electrical resistivity, magnetic susceptibility and 57Fe and 151Eu Mossbauer spectroscopy provide clear evidence that the ordering of the Fe moments observed at 190 K in undoped EuFe2As2 is completely suppressed in our 50% K doped sample, thus there is no coexistence between the Fe magnetic order and the superconducting state. However, short range ordering of the Eu moments is coexisting with the superconducting state below 15 K. A bump in the susceptibility well below Tc as well as a slight broadening of the Fe Mossbauer line below 15 K evidence an interplay between the Eu magnetism and the superconducting state.