  Intrinsic ferromagnetism is a crucial ingredient to realize quantum anomalous
Hall effect in quasi two dimensional materials, thus the search of intrinsic
ferromagnetic topological materials is one of the most concerned issues in the
field of topological phases of matter. In this work, combining magnetotransport
measurements, first principles calculations, and angle-resolved photoemission
spectroscopy studies, we find that in MnSb6Te10, the n = 2 member of the
MnSb2Te4/(Sb2Te3)n family, the strong magnetic competition realizes a fragile
ferromagnetic ground state, which whereas easily enters into ferrimagnetic and
the Z_2 antiferromagnetic topological insulator phase with warming to higher
temperature. Interestingly, the system stays in an inversion-symmetry-protected
axion insulator phase in the ferromagnetic ground state as well as in the
external magnetic field driven spin-polarized FM phase and can be converted
into a Weyl semimetal with multiple Weyl nodes in the valence bands with hole
doping, which are manifested by the measured notable intrinsic anomalous Hall
effect. Our work thus provides an intrinsic magnetic topological material which
is highly tunable into versatile topological phases by temperature, magnetic
field, as well as carrier doping.
