EuFe2(As1-xPx)2: reentrant spin glass and superconductivity

TL;DR

This study investigates EuFe2(As1-xPx)2 single crystals, revealing complex magnetic phases including a reentrant spin glass state that coexists with superconductivity, challenging existing phase diagrams.

Contribution

It uncovers a reentrant spin glass phase coexisting with superconductivity in EuFe2(As1-xPx)2, revising the understanding of its magnetic and superconducting interplay.

Findings

Discovery of a spin glass transition below 30K.

Coexistence of reentrant spin glass and superconductivity at x=0.2.

Revision of the phase diagram for EuFe2(As1-xPx)2.

Abstract

By systematic investigations of the magnetic, transport and thermodynamic properties of single crystals of EuFe2(As1-xPx)2 we explore the complex interplay of superconductivity and Eu2+ magnetism. Below 30K, two magnetic transitions are observed for all P substituted crystals suggesting a revision of the phase diagram. In addition to the canted A-type antiferromagnetic order of Eu2+ at approximately 20K, a spin glass transition is discovered at lower temperatures. Most remarkably, the reentrant spin glass state of EuFe2(As1-xPx)2 coexists with superconductivity around x = 0.2.