Electrical Spin State Manipulation in All-Magnet Heterojunctions Using a Ferromagnetic Spin Source

The ability to electrically manipulate spin states in magnetic materials is essential for the advancement of energy-efficient spintronic device, which is typically achieved in systems composed of a spin source and a magnetic target, where the magnetic state of the target is altered by a charge current. While theories suggest that ferromagnets could function as more versatile spin sources, direct experimental studies involving only the spin source and target layers have been lacking. Here electrical manipulation of spin states in noncolinear antiferromagnet Mn₃Sn using ferromagnets (Ni, Fe, NiFe, CoFeB) as the spin sources is reported. Both field-free switching and switching with an assistive field are achieved in Mn₃Sn/ferromagnet bilayers, where the switching polarity correlates with the sign of anomalous Hall effect of the ferromagnets. The experimental findings can be accounted for by the presence of spin currents arising from spin-dependent scattering within the ferromagnets. This finding provides valuable insights into the underlying mechanisms of spin-conversion in ferromagnets, offering an alternative spin source for novel technological applications.