Magnetic skyrmion generation by reflective spin-wave focusing

Self-Focusing Skyrmion Racetracks in Ferrimagnets

We theoretically study the dynamics of ferrimagnetic skyrmions in inhomogeneous metallic films close to the angular momentum compensation point. In particular, it is shown that the line of the vanishing angular momentum can be utilized as a self-focusing racetrack for skyrmions. To that end, we begin by deriving the equations of motion for the dynamics of collinear ferrimagnets in the presence of a charge current. The obtained equations of motion reduce to those of ferromagnets and antiferromagnets at two special limits. In the collective coordinate approach, a skyrmion behaves as a massive ch…

Spin-wave focusing induced skyrmion generation

We propose a new method to generate magnetic skyrmions through spin-wave focusing in chiral ferromagnets.A lens is constructed to focus spin waves by a curved interface between two ferromagnetic thin films with different perpendicular magnetic anisotropies. Based on the principle of identical magnonic path length, we derive the lens contour that can be either elliptical or hyperbolical depending on the magnon refractive index. Micromagnetic simulations are performed to verify the theoretical design. It is found that under proper condition magnetic skyrmions emerge near the focus point of the l…

Self focusing Hybrid Skyrmions in spatially varying canted ferromagnetic systems

Magnetic skyrmions are quasiparticle configurations in a magnetic film that can act as information carrying bits for ultrasmall, all-electronic nonvolatile memory. The skyrmions can be nucleated and driven by spin-orbit torque from a current driven in a heavy metal underlayer. Along its gyrotropic path, a Magnus force can cause a skyrmion to be annihilated at the boundaries. By combining interfacial and bulk Dzyaloshinskii-Moriya interactions (DMIs), for instance by using a B20 material on top of a heavy metal layer with high spin-orbit coupling, it is possible to engineer a hybrid skyrmion th…

Tailoring Optical Excitation to Control Magnetic Skyrmion Nucleation

In ferromagnetic multilayers, a single laser pulse with a fluence above an optical nucleation threshold can create magnetic skyrmions, which are randomly distributed over the area of the laser spot. However, in order to study the dynamics of skyrmions and for their application in future data technology, a controllable localization of the skyrmion nucleation sites is crucial. Here, it is demonstrated that patterned reflective masks behind a thin magnetic film can be designed to locally tailor the optical excitation amplitudes reached, leading to spatially controlled skyrmion nucleation on the n…

中心对称磁体中三子晶格反铁型和亚铁型斯格明子晶体

Three-sublattice antiferro-type and ferri-type skyrmion crystals in centrosymmetric magnets

本研究通过数值模拟三子晶格自旋模型，发现多子晶格自由度可稳定多种新型斯格明子晶体相，包括铁型、亚铁型和反铁型，为探索奇异磁结构提供了新途径。

磁性斯格明子中依赖堆叠的非互易输运

Stacking-dependent nonreciprocal transport in magnetic skyrmions

本研究理论提出中心对称磁体的拓扑自旋织构可产生非线性非互易输运，发现层状三角晶格斯格明子晶体的ABC堆叠结构无需自旋-轨道耦合即可产生面外非互易输运，揭示其机制并提出稳定该结构的有效自旋模型。