Mechanism study of strain-induced magnetic properties changes for nickel-based materials at atomic scale

Based on the magneto-mechanical coupling effect, magnetic non-destructive testing technology is widely used to test stress and defect in ferromagnetic materials. To analyze the effect of strain/stress on the atomic magnetism of Ni-based materials strain-induced changes of magnetic properties of FCC-Ni 2 × 2 × 2 supercell and its doped systems with Cu and Nb atoms are studied by the first principal density functional theory. Firstly, addition of Cu or Nb promote the expansion of nickel lattice, and Nb makes this effect more significant. Cu atoms enhance the magnetic moment of Ni atoms, while Nb atoms play an inhibitory role. Secondly, for uniaxial strain, the magnetic moments of atoms in the doping-free systems show a nearly monotonic increasing trend from compression to tension, while the doped systems show a trend of first increases and then decreases. Furthermore, for shear loading, the atomic magnetic moment decreases with increases of the shear strain. Further investigation shows that Ni atoms at different distances exhibit completely different magnetic behavior due to the influence of loadings and doping atoms. This study would be an important supplement to the physical mechanism of multi-field coupling in magnetic non-destructive testing.