Readout of an antiferromagnetic spintronics system by strong exchange coupling of Mn2Au and Permalloy

In antiferromagnetic spintronics, the read-out of the staggered magnetization or Neel vector is the key obstacle to harnessing the ultra-fast dynamics and stability of antiferromagnets for novel devices. Here, we demonstrate strong exchange coupling of Mn2Au, a unique metallic antiferromagnet that exhibits Neel spin-orbit torques, with thin ferromagnetic Permalloy layers. This allows us to benefit from the well-established read-out methods of ferromagnets, while the essential advantages of antiferromagnetic spintronics are only slightly diminished. We show one-to-one imprinting of the antiferromagnetic on the ferromagnetic domain pattern. Conversely, alignment of the Permalloy magnetization reorients the Mn2Au Neel vector, an effect, which can be restricted to large magnetic fields by tuning the ferromagnetic layer thickness. To understand the origin of the strong coupling, we carry out high resolution electron microscopy imaging and we find that our growth yields an interface with a well-defined morphology that leads to the strong exchange coupling. Antiferromagnets offer faster operation speed and immunity to stray fields, however, readout of the Neel vector is difficult. Here, Bommanaboyena et al present a heterostructure of a ferromagnet and antiferromagnet, combining easy readout with the benefits of antiferromagnetic spintronics.

Automated summary

In this study, strong exchange coupling between a unique metallic antiferromagnet Mn2Au and thin ferromagnetic Permalloy layers is demonstrated, allowing benefits from established read-out methods of ferromagnets while slightly diminishing the advantages of antiferromagnetic spintronics. Tuning the ferromagnetic layer thickness can restrict the reorientation of Mn2Au Neel vector by Permalloy magnetization. High resolution electron microscopy imaging reveals a well-defined interface morphology that leads to the strong exchange coupling in the heterostructure.