  Engineering the anomalous Hall effect (AHE) in the emerging magnetic
topological insulators (MTIs) has great potentials for quantum information
processing and spintronics applications. In this letter, we synthesize the
epitaxial Bi2Te3/MnTe magnetic heterostructures and observe pronounced AHE
signals from both layers combined together. The evolution of the resulting
hybrid AHE intensity with the top Bi2Te3 layer thickness manifests the presence
of an intrinsic ferromagnetic phase induced by the topological surface states
at the heterolayer-interface. More importantly, by doping the Bi2Te3 layer with
Sb, we are able to manipulate the sign of the Berry phase-associated AHE
component. Our results demonstrate the un-paralleled advantages of MTI
heterostructures over magnetically doped TI counterparts, in which the
tunability of the AHE response can be greatly enhanced. This in turn unveils a
new avenue for MTI heterostructure-based multifunctional applications.
