Universal patterns of skyrmion magnetizations unveiled by defect implantation

Abstract

Skyrmions are spin-swirling textures hosting wonderful properties with potential implications in information technology. Such magnetic particles carry a magnetization, whose amplitude is crucial to establish them as robust magnetic bits, while their topological nature gives rise to a plethora of exquisite features such as topological protection, the skyrmion and topological Hall effects as well as the topological orbital moment. These effects are all induced by an emergent magnetic field directly proportional to the three-spin scalar chirality, $\chi= (\mathbf{S}_i\times\mathbf{S}_j)\cdot \mathbf{S}_k$, and shaped by the peculiar spatial dependence of the magnetization. Here, we demonstrate the existence of novel chiral magnetizations emerging from the interplay of spin-orbit interaction and either $\chi$ or the two-spin vector chirality $\boldsymbol{\kappa} = \mathbf{S}_i\times\mathbf{S}_j$. By scrutinizing correlations among the spin, orbital (trivial and chiral) magnetizations, we unveil from ab-initio universal patterns, quantify the rich set of magnetizations carried by single skyrmions generated in PdFe bilayer on Ir(111) surface and demonstrate the ability to engineer their magnitude via controlled implantation of impurities. We anticipate that our findings can guide the design of disruptive storage devices based on skyrmionic bits by encoding the desired magnetization with strategic seeding of defects.