Campus Units

Physics and Astronomy, Ames Laboratory

Document Type

Article

Publication Version

Published Version

Publication Date

10-15-2019

Journal or Book Title

Physical Review B

Volume

100

Issue

16

First Page

161113(R)

DOI

10.1103/PhysRevB.100.161113

Abstract

SrCo2As2 is a peculiar itinerant magnetic system that does not order magnetically, but inelastic neutron-scattering experiments observe the same stripe-type antiferromagnetic (AF) fluctuations found in many of the Fe-based superconductors along with evidence of magnetic frustration. Here we present results from neutron diffraction measurements on single crystals of Sr(Co1-xNix)(2)As-2 that show the development of long-range AF order with Ni doping. However, the AF order is not stripe type. Rather, the magnetic structure consists of ferromagnetically aligned (FM) layers (with moments laying in the layer) that are AF arranged along c with an incommensurate propagation vector of (0 0 tau), i.e., a helix. Using high-energy x-ray diffraction, we find no evidence for a temperature-induced structural phase transition that would indicate a collinear AF order. This finding supports a picture of competing FM and AF interactions within the square transition-metal layers due to flat-band magnetic instabilities. However, the composition dependence of the propagation vector suggests that far more subtle Fermi surface and orbital effects control the interlayer magnetic correlations.

Comments

This article is published as Wilde, J. M., A. Kreyssig, D. Vaknin, N. S. Sangeetha, Bing Li, W. Tian, P. P. Orth, D. C. Johnston, B. G. Ueland, and R. J. McQueeney. "Helical magnetic ordering in Sr (Co 1− x Ni x) 2 As 2." Physical Review B 100, no. 16 (2019): 161113. DOI: 10.1103/PhysRevB.100.161113. Posted with permission.

Copyright Owner

American Physical Society

Language

en

File Format

application/pdf

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