Fractional antiferromagnetic skyrmion lattice induced by anisotropic couplings
Shang Gao, H. Diego Rosales, Flavia A. Gómez Albarracín, Vladimir Tsurkan, Guratinder Kaur, Tom Fennell, Paul Steffens, Martin Boehm, Petr Čermák, Astrid Schneidewind, Eric Ressouche, Daniel C. Cabra, Christian Rüegg, Oksana Zaharko
Abstract
Magnetic skyrmions are topological solitons with a nanoscale winding spin texture that hold promise for spintronics applications1–4. Skyrmions have so far been observed in a variety of magnets that exhibit nearly parallel alignment for neighbouring spins, but theoretically skyrmions with anti-parallel neighbouring spins are also possible. Such antiferromagnetic skyrmions may allow more flexible control than conventional ferromagnetic skyrmions5–10. Here, by combining neutron scattering measurements and Monte Carlo simulations, we show that a fractional antiferromagnetic skyrmion lattice is stabilized in MnSc2S4 through anisotropic couplings. The observed lattice is composed of three antiferromagnetically coupled sublattices, and each sublattice is a triangular skyrmion lattice that is fractionalized into two parts with an incipient meron (half-skyrmion) character11,12. Our work demonstrates that the theoretically proposed antiferromagnetic skyrmions can be stabilized in real materials and represents an important step towards their implementation in spintronic devices. Theoretically predicted fractional antiferromagnetic skyrmions are experimentally realized in MnSc2S4 and are found to originate from anisotropic couplings over nearest neighbours in the crystal lattice.