Mechanism of strain-induced magnetic properties changes for metal magnetic memory technology on atomic scale

Abstract

Magnetic non-destructive testing technology is widely used to detect stresses and defects in ferromagnetic materials based on the magneto-mechanical coupling effect. In the existing studies, calculated are the magnetic moment variations of the <i>α</i>-Fe system under axial tension and compression by using first-principles study, and the magneto-mechanical coupling mechanism is preliminarily discussed at an atomic level for the magnetic testing technology. In this work, taking the more complex doping systems Fe-C and Fe-Mn for examples, under different loading conditions of tension, compression and shearing, the coupling mechanisms such as the magnetic moment changes in different types of atomic doping systems are discussed in detail. The results show that the <i>α</i>-Fe and doping systems follow different changing laws of magnetic moments and energy under different types of strains. The detailed analyses of the density of states, the band structure, and the atomic magnetic moment show that doping elements change the morphology of band structure and the peak value of density of states by affecting the magnetic moment of Fe atoms, which leads the changing laws of magnetic moment and energy to be different from each other. In this work, discussed are the magneto-mechanical effects on the atomic level for ferromagnetic materials with different loading types, different doping elements and different element content. The results can be used as an important part of the multi-field coupling mechanism for magnetic testing technology.