Mixed Type of the Magnetic Order in Intrinsic Magnetic Topological Insulators Mn(Bi,Sb) 2 Te 4

It is known that Mn(Bi 1 – x Sb x ) 2 Te 4 is an intrinsic magnetic topological insulator, where the Dirac point can be localized at the Fermi level by substituting Bi atoms for Sb atoms to implement the quantum anomalous Hall effect and other unique quantum effects. It has already been shown that Mn(Bi 1 – x Sb x ) 2 Te 4 samples has antiferromagnetic order in a wide range of Sb concentration x = [0, 0.5]. In this paper a mixed type of magnetic ordering is experimentally demonstrated. This implies that there is both a ferromagnetic and an antiferromagnetic order in the system. We revealed the main reproducible magnetic characteristics of this magnetic structure, as well as their dependence on the concentration of Sb atoms.