Exchange coupling and magnetism of nanocrystalline γ′-Fe4−xNixN (0.2⩽x⩽0.8) compounds

The electronic structure and magnetism of nanocrystalline γ′-Fe4−xNixN (0.2⩽x⩽0.8) compounds have been studied with MS-Xα method. The results show that there are negative exchange couplings between atoms in the nanocrystalline γ′-Fe4−xNixN (0.2⩽x⩽0.8) compounds. The strength of the negative exchange coupling increases with increasing Ni atom concentration and the atomic spacing has a significant influence on the exchange coupling. A good agreement is obtained between calculations and experimental results.