Gradient-Induced Dzyaloshinskii-Moriya Interaction

The Dzyaloshinskii-Moriya interaction (DMI) that arises in the magnetic systems with broken inversion symmetry plays an essential role in topological spintronics. Here, by means of atomistic spin calculations, we study an intriguing type of DMI (g-DMI) that emerges in the films with composition gradient. We show that both the strength and chirality of g-DMI can be controlled by the composition gradient even in the disordered system. The layerresolved analysis of g-DMI unveils its additive nature inside the bulk layers and clarifies the linear thickness dependence of g-DMI observed in experiments. Furthermore, we demonstrate the g-DMI-induced chiral magnetic structures, such as spin spirals and skyrmions, and the g-DMI driven field-free spin-orbit torque (SOT) switching, both of which are crucial toward practical device application. These results elucidate the underlying mechanisms of g-DMI and open up a new way to engineer the topological magnetic textures.

Automated summary

In this study, we used atomistic spin calculations to investigate an intriguing type of Dzyaloshinskii-Moriya interaction (DMI) that emerges in films with composition gradient. We found that the strength and chirality of this DMI can be controlled by the composition gradient, even in disordered systems. Our study also demonstrated the DMI-induced chiral magnetic structures and field-free spin-orbit torque switching, both of which are crucial for practical device applications.