Abstract
The magnetic order in CaK(Fe1-xNix)4As4 (1144) single crystals (x=0.051 and 0.033) has been studied by neutron diffraction. We observe magnetic Bragg peaks associated with the same propagation vectors as found for the collinear stripe antiferromagnetic (AFM) order in the related BaFe2As2 (122) compound. The AFM state in 1144 preserves tetragonal symmetry and only a commensurate, noncollinear structure with a hedgehog spin-vortex crystal (SVC) arrangement in the Fe plane and simple AFM stacking along the c direction is consistent with our observations. The SVC order is promoted by the reduced symmetry in the FeAs layer in the 1144 structure. The long-range SVC order coexists with superconductivity, however, similar to the doped 122 compounds, the ordered magnetic moment is gradually suppressed with the developing superconducting order parameter. This supports the notion that both collinear and noncollinear magnetism and superconductivity are competing for the same electrons coupled by Fermi surface nesting in iron arsenide superconductors.
| Original language | English |
|---|---|
| Article number | 224521 |
| Journal | Physical Review B |
| Volume | 97 |
| Issue number | 22 |
| DOIs | |
| State | Published - Jun 28 2018 |
Funding
We are grateful for excellent assistance by D. S. Robinson with performing the high-energy x-ray diffraction experiments and for helpful discussions with P. P. Orth. Work at the Ames Laboratory was supported by the US Department of Energy (DOE), Basic Energy Sciences, Division of Materials Sciences and Engineering, under Contract No. DEAC02-07CH11358. A portion of this research used resources at the High Flux Isotope Reactor, a US DOE Office of Science User Facility operated by the Oak Ridge National Laboratory. This research used resources of the Advanced Photon Source, a US DOE Office of Science User Facility operated for the US DOE Office of Science by Argonne National Laboratory under Contract No. DE-AC02-06CH11357. W.R.M. was supported by the Gordon and Betty Moore Foundation's EPiQS Initiative through Grant No. GBMF4411.