Competing Magnetic Interactions in the Antiferromagnetic Kagome Semimetal Fe\(_{1-y}\)Co\(_y\)Sn

Abstract

Antiferromagnetic Kagome semimetal FeSn has gained significant attention due to the presence of topological flat bands and Dirac fermions. There has been immense interest to tune the bands with doping in FeSn for enhancing the magnetic and transport properties. Here, we report an experimental study of transport, magnetization, and electronic structure of Fe\(_{1-y}\)Co\(_y\)Sn as a function of Co-doping concentration (y). Variation in the temperature-dependent resistivity with increasing y is associated with the increase in spin-dependent scattering. Co doping in FeSn gives rise to canted antiferromagnetism with the decrease in the Neel transition temperature (\(T_{N}\)). The local moment of Co and Fe atoms has been estimated from the analysis of 3s core levels. The decrease in \(T_{N}\) with increasing y is due to the decrease in the local moment of Fe atoms. The systematic shift in the valence states away from the Fermi level (\(E_{F}\)), and the valence band broadening with the increase in y indicate an increase in the electron correlation and hybridization effects in Fe\(_{1-y}\)Co\(_y\)Sn. An increase in both electron correlation and hybridization with doping leads to the strong magnetic interaction between the local moments of Fe and Co atoms which gives rise to the canted antiferromagnetism in Fe\(_{1-y}\)Co\(_y\)Sn.