Field-free magnetization switching in CoPt induced by noncollinear antiferromagnetic Mn3Ga

The magnetic spin Hall effect (MSHE) may produce the out-of-plane spin current with z-direction polarization (az), thus allowing the field-free switching of perpendicular magnetization in ferromagnetic films. Here, we fabricate the epitaxial L11-CoPt/D019-Mn3Ga bilayers on MgO(111) substrates and characterize their magnetic and electrical transport properties. In the L11-CoPt/D019-Mn3Ga bilayers, we observe the spin-orbit torque switching of perpendicular magnetization under zero external field. The magnetization switching ratio and polarity are specifically related to the Neel vector direction of the antiferromagnetic Mn3Ga as well as the crystalline orientations which the pulse current is applied along. The field-free switching in the bilayers is attributed to the az spin current generated by the MSHE, which is driven by the reduced symmetry of Mn3Ga film with noncollinear spin structure.