Interface-driven chiral magnetism and current-driven domain walls in insulating magnetic garnets

Abstract

Magnetic oxides exhibit rich fundamental physics1–4 and technologically desirable properties for spin-based memory, logic and signal transmission5–7. Recently, spin–orbit-induced spin transport phenomena have been realized in insulating magnetic oxides by using proximate heavy metal layers such as platinum8–10. In their metallic ferromagnet counterparts, such interfaces also give rise to a Dzyaloshinskii–Moriya interaction11–13 that can stabilize homochiral domain walls and skyrmions with efficient current-driven dynamics. However, chiral magnetism in centrosymmetric oxides has not yet been observed. Here we discover chiral magnetism that allows for pure spin-current-driven domain wall motion in the most ubiquitous class of magnetic oxides, ferrimagnetic iron garnets. We show that epitaxial rare-earth iron garnet films with perpendicular magnetic anisotropy exhibit homochiral Néel domain walls that can be propelled faster than 800\u2009m\u2009s−1 by spin current from an adjacent platinum layer. We find that, despite the relatively small interfacial Dzyaloshinskii–Moriya interaction, very high velocities can be attained due to the antiferromagnetic spin dynamics associated with ferrimagnetic order.Spin currents from an adjacent Pt layer can drive homochiral Néel domain walls in centrosymmetric rare-earth iron garnet films at more than 800\u2009m\u2009s–1, taking advantage of the antiferromagnetic spin dynamics of the ferrimagnetic oxide.