Universal magnetic and structural behaviors in the iron arsenides

TL;DR

This paper investigates the universal magnetic and structural behaviors in iron arsenide superconductors, revealing two distinct universality classes of phase transitions linked to their structural and magnetic properties.

Contribution

It identifies commonalities in antiferromagnetic order parameters and compares phase transition behaviors across different iron arsenide compounds.

Findings

Two universality classes of magnetic phase transitions identified

Structural and magnetic phase transitions often coincide in these materials

Magnetic and structural behaviors are linked to their proximity in phase transitions

Abstract

Commonalities among the order parameters of the ubiquitous antiferromagnetism present in the parent compounds of the iron arsenide high temperature superconductors are explored. Additionally, comparison is made between the well established two-dimensional Heisenberg-Ising magnet, K$_2$NiF$_4$ and iron arsenide systems residing at a critical point whose structural and magnetic phase transitions coincide. In particular, analysis is presented regarding two distinct classes of phase transition behavior reflected in the development of antiferromagnetic and structural order in the three main classes of iron arsenide superconductors. Two distinct universality classes are mirrored in their magnetic phase transitions which empirically are determined by the proximity of the coupled structural and magnetic phase transitions in these materials.