Weak antilocalization and ferromagnetism in magnetic Weyl semimetal Co3Sn2S2

Abstract

Here, we report the 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 175 K, which is further verified through electrical transport measurements. Hysteresis is observed in ρ–T measurements in a cooling and a warming cycle, showing the presence of the first order phase transition and charge ordering in the synthesized sample. Synthesized Co3Sn2S2 exhibits a high magnetoresistance of around 230% at 2 K. 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 ±1 T (Tesla) are fitted with the Hikami Larkin Nagaoka model, which shows the presence of a weak antilocalization (WAL) effect in the synthesized Co3Sn2S2 crystal at low temperatures below 30 K. Angle dependent magnetotransport measurements confirm that the observed WAL is the topological surface state dominated phenomenon.