Topological Hall effect in bulk ferromagnet Cr\(_2\)Te\(_3\) embedded with black-phosphorus-like bismuth nanosheets

We implement the molecular beam epitaxy method to embed the black-phosphorus-like bismuth nanosheets into the bulk ferromagnet Cr\(_2\)Te\(_3\). As a typical surfactant, bismuth lowers the surface tensions and mediates the layer-by-layer growth of Cr\(_2\)Te\(_3\). Meanwhile, the bismuth atoms precipitate into black-phosphorus-like nanosheets with the lateral size of several tens of nanometers. In Cr\(_2\)Te\(_3\) embedded with Bi-nanosheets, we observe simultaneously a large topological Hall effect together with the magnetic susceptibility plateau and magnetoresistivity anomaly. As a control experiment, none of these signals is observed in the pristine Cr\(_2\)Te\(_3\) samples. Therefore, the Bi-nanosheets serve as seeds of topological Hall effect induced by non-coplanar magnetic textures planted into Cr\(_2\)Te\(_3\). Our experiments demonstrate a new method to generates a large topological Hall effect by planting strong spin-orbit couplings into the traditional ferromagnet, which may have potential applications in spintronics.