Reorientation of antiferromagnetism in Co-doped FeSn and its implications for Dirac electron states*

FeSn is an itinerant antiferromagnet with an Fe Kagome-lattice that hosts electronic Dirac states[1-2]. I will present magnetization measurements of single crystals of (Fe_1-xCo_x)Sn revealing the evolution and suppression of this magnetic order with Co substitution. We interpret the dramatic changes of the magnetic anisotropy to indicate a reorientation of the magnetic moments from perpendicular to parallel to the hexagonal c-axis and confirm this with neutron diffraction. It has been proposed that the Dirac nodes observed in FeSn should become gapped if the moments rotate as our data suggests[1]. We identify Co-substituted compositions that adopts both antiferromagnetic configurations at different temperatures. This system provides a unique opportunity to study how the details of magnetic order impact Dirac electron states.

[1] Z. Lin, et al. (2019), Arxiv 1906.05755v1.
[2] M. Kang, et al. (2019), Arxiv 1906.02167v1.