The evolution of magnetism in intrinsic magnetic insulator material MnBi₂Te₄(Bi₂Te₃)_n

Magnetic topological insulators (MTIs) are promising platforms for the observation of quantum anomalous Hall effect (QAHE), which is a long-expected dissipationless quantum transport phenomenon without applying external magnetic field. The recent progress on intrinsic MTI materials shed new light on the observation of higher temperature of QAHE. Here we grow the high-quality single crystals of three promising intrinsic MTI candidates MnBi₂Te₄(Bi₂Te₃)_n (n = 0,1,2). By magnetic measurement, we discover that the all three compounds show anti-ferromagnetic (AFM) behavior, while the magnetic transition temperature decreases when increasing the value n. Meanwhile, by transport measurement, anomalous Hall effect can be observed in all three samples and the behaviors are correspondingly consistent with the magnetic measurements. The AFM coupling becomes weaker since the critical magnetic field for anti-ferromagnetism to ferromagnetism transition becomes lower when increasing n, and net ferromagnetic moment retains in n = 1 and 2 under low temperature. We believe that the tunable magnetic and transport properties by controlling the component ratio in MnBi₂Te₄(Bi₂Te₃)_n provide an ideal platform to investigate the high-temperature QAH phase and the related physics.