Coexistence of magnetism and superconductivity in separate layers of the iron-based superconductor Li_{1-x}Fe_{x}(OH)Fe_{1-y}Se

TL;DR

This study investigates the coexistence of magnetism and superconductivity in Li_{1-x}Fe_{x}(OH)Fe_{1-y}Se, revealing that magnetic order persists below 10 K in both superconducting and nonsuperconducting samples, with evidence of a glassy magnetic state.

Contribution

It provides new insights into the magnetic properties of the hydroxide layer and its coexistence with superconductivity in this iron-based superconductor.

Findings

Magnetic order exists below 10 K in both superconducting and nonsuperconducting samples.

Magnetism persists into the superconducting state, indicating coexistence.

Evidence suggests a glassy magnetic state with iron clusters in the hydroxide layer.

Abstract

The magnetic properties attributed to the hydroxide layer of Li1-xFex(OH)Fe1-ySe have been elucidated by the study of superconducting and nonsuperconducting members of this family. Both ac magnetometry and muon spin relaxation measurements of nonsuperconductors find a magnetic state existing below approximately 10 K which exhibits slow relaxation of magnetization. This magnetic state is accompanied by a low-temperature heat capacity anomaly present in both superconducting and nonsuperconducting variants suggesting that the magnetism persists into the superconducting state. The estimated value of magnetic moment present within the hydroxide layer supports a picture of a glassy magnetic state, probably comprising clusters of iron ions of varying cluster sizes distributed within the lithium hydroxide layer.