  We propose a phase diagram for FexBi2Te3 (0 < x < 0.1) single crystals, which
belong to a class of magnetically bulk-doped topological insulators. The
evolution of magnetic correlations from ferromagnetic- to antiferromagnetic-
gives rise to topological phase transitions, where the paramagnetic topological
insulator of Bi2Te3 turns into a band insulator with ferromagnetic-cluster
glassy behaviours around x ~ 0.025, and it further evolves to a topological
insulator with valence-bond glassy behaviours, which spans over the region
between x ~ 0.03 up to x ~ 0.1. This phase diagram is verified by measuring
magnetization, magnetotransport, and angle-resolved photoemission spectra with
theoretical discussions.
