Room-temperature stabilization of antiferromagnetic skyrmions in synthetic antiferromagnets

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 shall lift these limitations. Here we
demonstrate that room-temperature antiferromagnetic skyrmions can be stabilized in synthetic antiferromagnets (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.