Weak antilocalization and ferromagnetism in magnetic Weyl semimetal Co3Sn2S2

TL;DR

This study successfully synthesizes and characterizes magnetic Weyl semimetal Co3Sn2S2, revealing ferromagnetism, high magnetoresistance, and weak antilocalization effects linked to topological surface states and bulk magnetic properties.

Contribution

First demonstration of synthesis and detailed characterization of magnetic Weyl semimetal Co3Sn2S2 showing ferromagnetism and topological transport phenomena.

Findings

Ferromagnetic transition at ~175K confirmed by magnetization and heat capacity.

High magnetoresistance of around 230% at 2K observed.

Weak antilocalization effect detected below 30K in magnetoconductivity data.

Abstract

Here we report successful synthesis of single crystalline magnetic Weyl semimetal Co3Sn2S2. The synthesized crystal is characterized through various tools viz. X-ray diffraction, field emission electron microscopy and X-ray photoelectron spectroscopy. A clear ferromagnetic transition is observed in magnetization and heat capacity at around 175K, which is further verified through electrical transport measurements. Hysteresis is observed in R-T measurements in cooling and warming cycle, showing the presence of first order phase transition and charge ordering in the synthesized sample. The synthesized Co3Sn2S2 exhibits high magnetoresistance of around 230% at 2K. The transport phenomenon in synthesized Co3Sn2S2 appears to have contributions from topological surface states at low temperature below say 70 K, and above that the same is found to be strongly dependent on its bulk magnetic state. Magnetoconductivity data at low fields of up to plus minus 1T (Tesla) is fitted with Hikami Larkin Nagaoka model, which shows the presence of weak antilocalization effect in synthesized Co3Sn2S2 crystal at low temperatures below 30K.