Spin-Orbit Coupling in Single-Layer Ferrimagnets: Direct Observation of Spin-Orbit Torques and Chiral Spin Textures

We demonstrate that the effects of spin-orbit coupling and inversion asymmetry exist in a single Gd-Fe-Co ferrimagnetic layer, even without a heavy-metal interface. We use electric transport measurements to quantify the spin-orbit torques. We measure the Dzyaloshinskii-Moriya interaction using the Brillouin light-scattering measurement technique, and we observe the resulting chiral magnetic textures using x-ray photoemission electron microscopy. We attribute these effects to a composition variation along the thickness that we observe by scanning transmission electron microscopy. We show that these effects can be optimized by varying the Gd-Fe-Co thickness or in combination with interfacial effects.