Room-temperature magnetic skyrmions in multilayers

Magnetic skyrmions are topological spin structures that are promising candidates for current-driven memory devices because of their high mobility at ultralow current densities. In magnetic multilayers, the interplay of various interactions, including the Heisenberg exchange, dipolar interactions, magnetic anisotropy, and interfacial Dzyaloshinskii-Moriya interactions, is key to forming and stabilizing magnetic skyrmions. In this work, the efficient conversion of chiral stripe domains into N\'{e}el skyrmions through a geometrical constriction patterned in a Ta/CoFeB/TaO$_{\mathrm{x}}$ trilayer film at room temperature is presented. This is enabled by an interfacial Dzyaloshinskii-Moriya interaction, and laterally divergent current-induced spin-orbit torques. The generation of magnetic skyrmions solely by the divergent spin-orbit torques through a nonmagnetic point contact is further demonstrated. When increasing the current density, the skyrmion Hall effect, the accumulation of skyrmions at one side of the device, is directly observed using magneto-optical Kerr effect microscopy.