Room-temperature stabilization of antiferromagnetic skyrmions in synthetic antiferromagnets

William Legrand , Davide Maccariello , Fernando Ajejas , Sophie Collin , Aymeric Vecchiola , Karim Bouzehouane , N. Reyren (1) , Vincent Cros , Albert Fert

1 Laboratoire Albert Fert (ex-UMPhy Unité mixte de physique CNRS/Thales)

Room-temperature skyrmions in ferromagnetic films and multilayers show promise for encoding information bits in new computing technologies. Despite recent progress, ferromagnetic order generates dipolar fields that prevent ultrasmall skyrmion sizes, and allows a transverse deflection of moving skyrmions that hinders their efficient manipulation. Antiferromagnetic skyrmions could lift these limitations. Here we demonstrate that room-temperature antiferromagnetic skyrmions can be stabilized in synthetic antiferro-magnets (SAFs), in which perpendicular magnetic anisotropy (PMA), antiferromagnetic coupling and chiral order can be adjusted concurrently. Utilizing interlayer electronic coupling to an adjacent bias layer (BL), we demonstrate that spin-spiral states obtained in a SAF with vanishing PMA can be turned into isolated antiferromagnetic skyrmions. We also provide model-based estimates of skyrmion size and stability, showing that room-temperature antiferromagnetic skyrmions below 10 nm in radius can be anticipated in further optimized SAFs. Antiferromagnetic skyrmions in SAFs may thus solve major issues associated with ferromagnetic skyrmions for low-power spintronic devices.

Domaines: Matière Condensée [cond-mat]

William Legrand, Davide Maccariello, Fernando Ajejas, Sophie Collin, Aymeric Vecchiola, et al.. Room-temperature stabilization of antiferromagnetic skyrmions in synthetic antiferromagnets. Nature Materials, 2020, 19 (1), pp.34-42. ⟨10.1038/s41563-019-0468-3⟩. ⟨hal-02990727⟩