Magnetic skyrmions are topologically protected nanoscopic vortices of magnetization that can be stabilized in a magnetic field. Magnetocrystalline anisotropy (K1) in uniaxial crystal structures is required to be strong enough to resist self-demagnetization in the shape of a thin lamella or film. We discovered antiskyrmions in Mn1.4
PtSn with uniaxial anisotropy and spin-reorientation transition at low temperature. Inspired by Mn1.4
PtSn, we further discovered new skyrmion bubble materials with similar features of perpendicular anisotropy and spin-reorientation in traditional hard magnetic materials, MnBi and Nd2
B, which exhibit a large topological Hall effect at room temperature. However, spin-reorientation transition is unfavourable in hard magnets. To avoid this, new rare-earth-free hard magnetic materials with a strong K1 at room temperature, including Rh2
CoSb and (Fe,Co)2
(P,Si), were discovered at Felser’s department.