Doping-induced Spin Reorientation in Kagome Magnet TmMn6Sn6

TL;DR

This study investigates how minimal Ga doping in TmMn6Sn6 affects its magnetic anisotropy, revealing a transition from easy-plane to easy-axis magnetization and providing insights into the role of doping on magnetic properties.

Contribution

The paper presents combined experimental and theoretical analysis of Ga doping effects on magnetic anisotropy in TmMn6Sn6, highlighting the sensitivity of magnetic textures to doping levels.

Findings

Ga doping gradually switches magnetic anisotropy from easy-plane to easy-axis.

Magnetic properties are highly sensitive to small Ga concentrations.

First principles calculations support experimental observations.

Abstract

The kagome-lattice compounds RMn6Sn6 (R is a rare earth element), where the Mn atoms form a kagome net in the basal plane, are currently attracting a great deal of attention as they have been shown to host complex magnetic textures and electronic topological states strongly sensitive to the choice of the R atom. Among the magnetic R atoms, TmMn6Sn6 orders with the easy-plane magnetization forming a complex magnetic spiral along the c-axis. Previous neutron studies, carried on polycrystalline, samples found that Ga doping changes the magnetic anisotropy from easy-plane to easy-axis. Here we present magnetic and magnetotransport measurements on a single crystal and first principles calculations in the doping series of TmMn6Sn6-xGax. We find that the magnetic properties are highly sensitive even to a small concentration of Ga. With minimal Ga substitution, the easy-plane anisotropy is maintained, which gradually changes to the easy-axis anisotropy with increasing Ga. We discuss these observations with respect to the effect of Ga doping on magnetocrystalline anisotropy and Tm crystal field