Thickness-dependent perpendicular magnetic anisotropy and topological Hall effect in magnetic Weyl Co2MnGa and topological insulator Bi2Te3–based heterostructures

Review article, 2026

We have investigated the magnetic and transport properties of a unique combination of the topological Weyl ferromagnet (FM) Co2MnGa (CMG) and the topological insulator (TI) Bi2Te3 (BT) in order to explore quantum materials and their heterostructures with nontrivial topology in real space as well as momentum space. The thickness- and temperature-dependent properties of this heterostructure are studied in detail. The interfacial perpendicular magnetic anisotropy is observed in Co2MnGa at a thickness as high as 3 nm. The thickness-dependent tuning of the Fermi level leads to distinct transport characteristics in CMG(t)/BT heterostructures. The study also reports two unconventional observations in the Hall effect, i.e., the sign reversal of the anomalous Hall effect and the emergence of the topological Hall effect, both of which exhibit a significant dependence on temperature. The topological Hall effect, characterized by a high squareness ratio and a large Hall resistivity value of ∼189 ncm at 5 K, is observed in a wide temperature range below Tc in the CMG(7 nm)/BT(10 nm) heterostructure. This effect can be attributed to the presence of chiral magnetic textures induced by the interfacial Dzyaloshinskii- Moriya interaction, arising from the strong spin-orbit coupling (SOC) of BT. This conclusion is supported by the absence of such unconventional signatures in transport and magnetic measurements in another similar series CMG(t)/W(10 nm). Therefore, the interplay of strong intrinsic Berry curvature in CMG(as deduced from scaling mechanisms) and the high SOC of BT enable the FM/TI combination to host unconventional spin textures, which may provide an important building block for the next generation of spintronic devices.