Critical Behavior of the Magnetization in Heusler Alloy Co₂TiGa₀.₈Sn₀.₂

We report the critical behavior of the magnetization in Heusler alloy Co2TiGa0.8Sn0.2 as a potential candidate of high spin polarized materials with the characteristics of topological Weyl fermions. The Weyl semimetals are materials of great interest for applying spintronics devices, due to their unusual magnetoelectronic and magnetothermal properties. The magnetic properties of the synthesized Heusler alloy Co2TiGa0.8Sn0.2 are investigated around the Curie temperature TC. The magnetic isotherm measurements of Co2TiGa0.8Sn0.2 around TC exhibit that the critical exponent δ is deduced to be 4.455(4) in high maximum applied field of 50 kOe and 4.823(9) in low maximum applied field of 10 kOe, respectively. Both δ values are different from 3.0 derived by the conventional molecular field theory, but they are close to 5.0 predicted by the spin fluctuation theory for the itinerant electron ferromagnets. Possible origins for the discrepancy between experimental results and theoretical models are also discussed.