Sn thin films*

Mn₃X(X=Sn, Ga, Ge) antiferromagnetic (AFM) Weyl semimetals have attracted significant research due to their large Berry phase effects and potential for applications[1,2]. The temperature range for the anti-chiral magnetic phase with large topological effects varies for each of these materials, the highest temperature being the Neel temperature (T_N). Thin film forms of Mn₃Sn are routinely studied [3], however, in Mn₃Sn the anti-chiral magnetic phase has a limited temperature range (≈260-420K). To fully exploit the device possibilities, ranging from AFM spintronics [1-3] to unconventional superconducting spintronics based on Mn₃X/superconductor structures [4], one needs to engineer these Mn₃X thin film systems maximizing the Berry phase effects over a wide temperature range. In this work we present sputtered Mn₃Sn_1-xGa_x thin films in which the anti-chiral magnetic phase of Mn₃Sn is systematically modified with Ga doping. Our detailed structural characterization of Mn₃Sn_1-xGa_x reveals a systematic linear variation of the lattice parameters between Mn₃Sn (for x=0) and Mn₃Ga (for x=1) satisfying Vegard’s law of a substitutional solid solution. Temperature dependent Hall effect and magnetization measurements confirm a giant enhancement of anomalous Hall conductivity over a wide temperature range (extending from »500K down to at least 10K), and a systematic enhancement of T_N (from ≈420K to ≈500K) with Ga addition. In conclusion, our work presents a route for engineering topological effects in Mn₃X systems.