Abstract：Magnetic skyrmions is a kind of important topological magnetic structure in ferromagnetic materials. Due to its novel multi-physics coupling between the magnetic, electric, mechanical and thermal fields, magnetic skyrmions has potential applications in the future spintronic devices. However, the magnetic skyrmions are stable only at an external magnetic field, which limits its potential in applications. In this work, based on a real-space multiferroic phase field model, we demonstrate that the magnetic skyrmions can be stabilized by the polar skyrmions via interfacial deformation in the multiferroic composite. The multiferroic composite thin film consists of MnSi, BaTiO3 and SrTiO3 components. When an electric field is applied and then removed from the multiferroic thin film, an out-of-plane upward polar vortex shows in the BaTiO3 component. After applying a reverse electric field to the thin film, the polarizations outside the vortex in the SrTiO3 become downward. Hence, the polar skyrmions are obtained in the ferroelectric layer of the multiferroic composite. Because of the electrostrictive effect, the nonuniform polarizations distributions in the ferroelectric layer generate a periodic non-uniform deformation in the interface between ferroelectric and ferromagnetic layers. This nonuniform interfacial deformation can stabilize the magnetic skyrmions in the ferromagnetic layer without an external field, via magnetostrictive effect. The present work shows that the topological magnetic structures in the multiferroic composites can be controlled by the electro-magneto-elasticity coupling, which provides new ideas for the designs of the topological magnetic structure-based spintronic devices.
2020, Vol. 41 
