Magnetotransport study on large number MnSb₂Te₄ nanoflakes

The new family of intrinsically magnetic van-der-Waals layered topological insulators Mn(Bi,Sb)₂Te₄, with strong spin-orbit coupling, is of great interest to investigate the interplay between topology and magnetic order in electronic band structures. However, intrinsic disorder in these compounds both poses an experimental challenge in realizing the topological states. Especially in MnSb₂Te₄, the significant intrinsic Mn-Sb antisite intermixing has a strong influence on the overall magnetic –and possibly topological- properties. Here, we present a comparative magnetotransport study of ferromagnetic MnSb₂Te₄ on a large number of devices fabricated by mechanical exfoliation from the same single crystal. We evidence a striking thickness-dependence of the magnetic properties such as the Curie-temperature and the coercive field, which is further underlined by bulk magnetometry measurements. By combining the results with a high angle annular dark field scanning transmission electron microscopy (HAADF-STEM) structural analysis of the crystal, we discuss the thickness-dependent properties in the context of magnetic antisite intermixing and surface oxidation.