Magnetic phase transition, magnetoresistance, and anomalous Hall effect in Ga-substituted YMn6Sn6 with a ferromagnetic kagome lattice

Abstract

The $\mathrm{Hf}{\mathrm{Fe}}_{6}{\mathrm{Ge}}_{6}$-type $R{\mathrm{Mn}}_{6}{\mathrm{Sn}}_{6}$, a metallic system consisting of ferromagnetic kagome planes of Mn, has been recently shown to be a candidate hosting topological electronic properties. In this paper, we report magnetic and electronic properties in $\mathrm{Y}{\mathrm{Mn}}_{6}{\mathrm{Sn}}_{6\ensuremath{-}x}{\mathrm{Ga}}_{x}$ single crystals via magnetic susceptibility, electrical transport, and single-crystal neutron diffraction measurements. We show that the magnetic ground state of $\mathrm{Y}{\mathrm{Mn}}_{6}{\mathrm{Sn}}_{6\ensuremath{-}x}{\mathrm{Ga}}_{x}$ ($0\ensuremath{\le}x\ensuremath{\le}0.61$) evolves from incommensurate antiferromagnet to ferromagnet with increasing Ga substitution $x$, a feature which is accompanied by the decrease in magnetoresistance. Furthermore, the topological Hall effect observed in the pristine compound is absent in the Ga-substituted ones; instead, the anomalous Hall effect persists which may be associated with the Berry curvature of gapped Dirac bands near the Fermi energy. These results suggest strong correlation between electronic properties and magnetism in this topological magnet that can be readily tuned via Ga substitution.