Search for the new rare-earth free iron-based permanent magnets*

Permanent magnets are irreplaceable for many technological applications. Therefore new magnetic materials, that are cheap and abundant, are vital for the modern society. A good permanent magnet must have a high Curie temperature, high saturation magnetization and uniaxial magnetocrystilline anisotropy. Rare-earth free Fe-rich systems like the hexagonal close-packed Fe₃Sn compound are promising candidates. However, its magnetocrystalline anisotropy is planar. Alloying is a possibility for changing the easy axis of magnetization.
We have calculated from first principles the electronic structure and magnetic properties of ferromagnetic Fe₃Sn doped with Si, P, Ga, Ge, As, Se, In, Sb, Te, Pb, and Bi on the Sn sublattice as well as with the Mn phase-stabilizer on the iron sublattice. We discuss the influence of the different dopants on the magnetocrystalline anisotropies and Curie temperatures of Fe₃Sn and suggest new stable/metastable ferromagnetic phases with uniaxial anisotropy suitable for the development of advanced permanent magnets.