  Heterostructures having both magnetism and topology are promising materials
for the realization of exotic topological quantum states while challenging in
synthesis and engineering. Here, we report natural magnetic van der Waals
heterostructures of (MnBi2Te4)m(Bi2Te3)n that exhibit controllable magnetic
properties while maintaining their topological surface states. The interlayer
antiferromagnetic exchange coupling is gradually weakened as the separation of
magnetic layers increases, and an anomalous Hall effect that is well coupled
with magnetization and shows ferromagnetic hysteresis was observed below 5 K.
The obtained homogeneous heterostructure with atomically sharp interface and
intrinsic magnetic properties will be an ideal platform for studying the
quantum anomalous Hall effect, axion insulator states, and the topological
magnetoelectric effect.
