  Two dimensional magnetic materials, with tunable electronic properties could
lead to new spintronic, magnetic and magneto-optic applications. Here, we
explore intrinsic magnetic ordering in two dimensional monolayers of transition
metal tri-halides (MX$_3$, M = V, Cr, Mn, Fe and Ni, and X = F, Cl, Br and I),
using density functional theory. We find that other than FeX$_3$ family which
has an anti-ferromagnetic ground state, rest of the trihalides are
ferromagnetic. Amongst these the VX$_3$ and NiX$_3$ family are found to have
the highest magnetic transition temperature, beyond the room temperature. In
terms of electronic properties, the tri-halides of Mn and Ni are either half
metals or Dirac half metals, while the tri-halides of V, Fe and Cr are
insulators. Among all the trihalides studied in this paper, we find the
existence of very clean spin polarized Dirac half metallic state in MnF$_3$,
MnCl$_3$, MnBr$_3$, NiF$_3$ and NiCl$_3$. These spin polarized Dirac half
metals will be immensely useful for spin-current generation and other
spintronic applications.
