Enhancing magnetic anisotropy and stability of α″-Fe16N2 phase by Co and V co-substitution

Employing first-principles density functional calculations, we investigate critical effects of V and Co co-substitution on the structural stability and intrinsic magnetic properties of α″-phase Fe16N2. We demonstrate that only 1 or 2 V substitutes per formula unit stabilize the α″ phase and enhance uniaxial magnetic anisotropy (Ku) up to 1.1 MJ m−3, which is nearly 2 times that of 0.6 MJ m−3 in α″-Fe16N2. It is further predicted that Ku can even reach up to 1.8 MJ m−3 in Fe12V2Co2N2 with good stability. These results provide an instructive guideline for simultaneous enhancement of the structural stability and energy product in 3d-only permanent magnets.