  Using the real-space Hartree Fock approximation, the magnetic phase diagram
of a five-orbital Hubbard model for the iron-based superconductors is studied
varying the electronic density $n$ in the range from 5 to 7 electrons per
transition metal atom. The Hubbard interaction $U$ is also varied, at a fixed
Hund coupling $J/U=0.25$. Several qualitative trends and a variety of competing
magnetic states are observed. At $n$=5, a robust G-type antiferromagnetic
insulator is found, in agreement with experimental results for BaMn$_2$As$_2$.
As $n$ increases away from 5, magnetic states with an increasing number of
nearest-neighbors ferromagnetic links become energetically stable. This
includes the well-known C-type antiferromagnetic state at $n$=6, the E-phase
known to exist in FeTe, and also a variety of novel states not found yet
experimentally, some of them involving blocks of ferromagnetically oriented
spins. Regions of phase separation, as in Mn-oxides, have also been detected.
Comparison with previous theoretical investigations indicate that these
qualitative trends may be generic characteristics of phase diagrams of
multiorbital Hubbard models.
