Synthesis and characterization of a strong ferromagnetic and high hardness intermetallic compound Fe₂B

Magnetic materials attract great attention due to their fundamental importance and practical application. However, the relatively inferior mechanical properties of traditional magnetic materials limit their application in a harsh environment. In this work, we report an outstanding magnetic material that exhibits both fantastic mechanical and excellent magnetic properties, CuAl2-type Fe2B, synthesized by the high pressure and high temperature method. The magnetic saturation of Fe2B is 156.9 emu g-1 at room temperature and its Vickers hardness is 12.4 GPa which outclasses those of traditional magnetic materials. It exhibits good conductivity with a resistivity of 5.6 × 10-7 Ω m. Fe2B is a promising strong ferromagnetic material with high hardness, which makes it a good candidate for multifunction applications in a harsh environment. The high hardness of Fe2B originates from the Fe-B bond framework, and the strong ferromagnetism is mainly attributed to the large number of unpaired Fe 3d electrons. The competition of Fe 3d electrons to fall into Fe-B bonds or Fe-Fe bonds is the main factor for its magnetism and hardness. This work bridges the chasm between strong ferromagnetism and high hardness communities.