Several cobalt-based Heusler alloys have been predicted to exhibit Weyl Semimetal behavior due to time reversal symmetry breaking. Co 2 TiGe is one of the predicted ferromagnetic Weyl semimetals. In this work, we report weak localization and small anomalous Hall conductivity in half-metallic Co 2 TiGe thin films grown by molecular beam epitaxy. The longitudinal resistivity shows semimetallic behavior. Elaborate analysis of longitudinal magnetoconductance shows the presence of a weak localization quantum correction present even up to room temperature and reduction in dephasing length at lower temperature. Negative longitudinal magnetoresistance is observed from 5 to 300 K, but at 300 K magnetoresistance becomes positive above 0.5 T magnetic field. The anomalous Hall effect has been investigated in these thin films. The measured anomalous Hall conductivity decreases with increasing temperature, and a small anomalous Hall conductivity has been measured at various temperatures which may be arising due to both intrinsic and extrinsic mechanisms.

Transition metal telluride CoTe nanostructures have been synthesized using a wet-chemical method. These nanostructures exhibit NiAs-type hexagonal crystal structure with a space group of P63/mmc. The magnetic measurements show spontaneous magnetization and hysteresis, and the coercivity increases with a decrease in temperature. The saturation magnetization was calculated to be around 0.2 μB/Co atom. The magnetic transition temperature was found to be above room temperature similar to that of the bulk CoTe. The measured bandgap of the nanostructures is 2.15 eV and they exhibit p-type semiconducting behavior.

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