  In this work we perform a systematic calculation of the Fe-Ta phase diagram
to discover novel hard magnetic phases. By using structure prediction methods
based on evolutionary algorithms, we identify two new energetically stable
magnetic structures: a tetragonal Fe$_3$Ta (space group 122) and cubic Fe$_5$Ta
(space group 216) binary phases. The tetragonal structure is estimated to have
both high saturation magnetization ($\mu_0$M$_s$=1.14 T) and magnetocrystalline
anisotropy (K$_1$=2.17 MJ/m$^3$) suitable for permanent magnet applications.
The high-throughput screening of magneto-crystalline anisotropy also reveals
two low energy metastable hard magnetic phases: Fe$_5$Ta$_2$ (space group 156)
and Fe$_{6}$Ta (space group 194), that may exhibit intrinsic magnetic
properties comparable to SmCo$_5$ and Nd$_2$Fe$_{14}$B, respectively.
