Magnetization reversal of giant perpendicular magnetic anisotropy at the magnetic-phase transition in FeRh films on MgO

Phenomena originated from spin-orbit interaction, such as magnetic anisotropy (MA), Rashba-type interactions, or topological insulators, have drawn huge attention for its intriguing physics. In particular, the search for a novel antiferromagnetic material, with potentially large perpendicular MA (PMA), has been becoming very intensive for next-generation high density memory applications. Here, we propose that substitutions of transition metals Ru and Ir, neighboring and same group elements in the periodic table, for the Rh site in the vicinity of surface can induce a substantially large PMA, up to an order of magnitude of 20 erg/cm2, in FeRh films on MgO. The main driving mechanism for this huge PMA is the interplay between the dxy and dx2-y2 states of strong spin-orbit 4d and 5d orbitals. Further investigations demonstrate that magnetization direction of PMA undergoes a transition into an in-plane magnetization at the antiferromagnetic-to-ferromagnetic phase transition, which provides a viable route for achieving large and switchable PMA associated with the magnetic-phase transition in antiferromagnetic spintronics.