Local magnetism, magnetic order and spin freezing in the 'nonmetallic metal' FeCrAs [dataset]

We present the results of x-ray scattering and muon-spin relaxation (μ+SR) measurements on the iron-pnictide compound FeCrAs. Polarized non-resonant magnetic x-ray scattering results reveal the 120° periodicity expected from the suggested three-fold symmetric, noncollinear antiferromagnetic structure. μ+SR measurements indicate a magnetically ordered phase throughout the bulk of the material below TN = 105(5) K. There are signs of fluctuating magnetism in a narrow range of temperatures above TN involving low-energy excitations, while at temperatures well below TN behaviour characteristic of freezing of dynamics is observed, likely reflecting the effect of disorder in our polycrystalline sample. Using density functional theory we propose a distinct muon stopping site in this compound and assess the degree of distortion induced by the implanted muon.