Incommensurate spin-density wave order in electron-doped BaFe2As2 superconductors

TL;DR

This study reveals the transition from commensurate to incommensurate spin-density wave order in electron-doped BaFe2As2 superconductors, highlighting the itinerant magnetic behavior linked to Fermi surface nesting.

Contribution

It provides direct neutron diffraction evidence of incommensurate magnetic order in BaFe2As2 with Co doping, advancing understanding of magnetic states in iron-based superconductors.

Findings

Incommensurate magnetic order appears between x=0.056 and 0.06 Co doping.

Incommensurability manifests as a small transverse splitting from the commensurate wave vector.

Results support the Fermi surface nesting mechanism driving spin-density wave formation.

Abstract

Neutron diffraction studies of Ba(Fe[1-x]Co[x])2As2 reveal that commensurate antiferromagnetic order gives way to incommensurate magnetic order for Co compositions between 0.056 < x < 0.06. The incommensurability has the form of a small transverse splitting (0, +-e, 0) from the nominal commensurate antiferromagnetic propagation vector Q[AFM] = (1, 0, 1) (in orthorhombic notation) where e = 0.02-0.03 and is composition dependent. The results are consistent with the formation of a spin-density wave driven by Fermi surface nesting of electron and hole pockets and confirm the itinerant nature of magnetism in the iron arsenide superconductors.