First-Principles Study on the Stability, Site Preference, Electronic Structure and Magnetism of Alloyed FeB with NiP-Type Structure.

First-principles calculations were performed to investigate the site preference of alloying elements, and the effect of alloying elements on stability, electronic structure and magnetism of NiP-type FeB. The calculated energies suggested that all studied compounds are thermodynamically stable while it is relatively difficult to synthesize the (Fe,Cu)B, (Fe,W)B and (Fe,Nb)B. The (Fe,W)B is the most stable compound from the view of cohesive energy. Mn element prefers to occupy the Fe2 site, whereas the others are more likely to reside in the Fe1 site. It can be found from the electronic structures that the DOSs of both FeB and alloyed FeB are dominated by Fe-d states, and all the compounds mainly contain Fe-B covalent bond, Fe-Fe covalent bond and Fe-Fe metallic bond. Based on the magnetic moments (Ms) results, it can be known that the FeB, (Fe,Mn)B, (Fe,Co)B, (Fe,Ni)B and (Fe,Cu)B are ferromagnetic compounds, whereas the others are ferrimagnetic compounds. Only Mn and Co are able to enhance the magnetism of FeB. Moreover, Mn is the most favorable candidate for improving the magnetic properties of FeB among the alloying elements. These results can be used to guide the composition design and performance optimization of magnetic materials containing FeB with NiP-type structure.