Wigner solids of domain wall skyrmions

Topological Hall effect instigated in kagome Mn3-xSn due to Mn-deficit induced noncoplanar spin structure

Magnetic topological semimetals are manifestations of the interplay between electronic and magnetic phases of matter, leading to peculiar characteristics such as the anomalous Hall effect (AHE) and the topological Hall effect (THE). Mn3Sn is a time-reversal symmetry-broken magnetic Weyl semimetal showing topological characteristics within the Kagome lattice network. This study reveals a large THE in Mn2.8Sn (6% Mn deficit Mn3Sn) at room temperature in thexy-plane, despite being an antiferromagnet. We argue that the magnetocrystalline anisotropy induced noncoplanar spin structure is responsible for the observed THE in these systems. Further, the topological properties of these systems are highly anisotropic, as we observe a large AHE in thezx-plane. We find that Fe doping at the Mn site, Mn3-xFexSn (x= 0.2, 0.25, & 0.35), tunes the topological properties of these systems. These findings promise the realization of potential topotronic applications at room temperature.

Tuning of electrical, magnetic, and topological properties of magnetic Weyl semimetal Mn3+xGe by Fe doping

We report on the tuning of electrical, magnetic, and topological properties of the magnetic Weyl semimetal (Mn3+xGe) by Fe doping at the Mn site, Mn(3+x)-δFeδGe (δ= 0, 0.30, and 0.62). Fe doping significantly changes the electrical and magnetic properties of Mn3+xGe. The resistivity of the parent compound displays metallic behavior, the system withδ= 0.30 of Fe doping exhibits semiconducting or bad-metallic behavior, and the system withδ= 0.62 of Fe doping demonstrates a metal-insulator transition at around 100 K. Further, we observe that the Fe doping increases in-plane ferromagnetism, magnetocrystalline anisotropy, and induces a spin-glass state at low temperatures. Surprisingly, topological Hall state has been noticed at a Fe doping ofδ= 0.30 that is not found in the parent compound or withδ= 0.62 of Fe doping. In addition, spontaneous anomalous Hall effect observed in the parent system is significantly reduced with increasing Fe doping concentration.