Unit cell thick ferrimagnetic Mn₃Z Heusler Domain Wall motion

Antiferromagnets and ferrimagnets are of particular interest for spintronic devices. In this talk, we present the Domain Wall (DW) motion of Mn₃Z (Z=Ge, Sn, Sb) Heuslers, using the chemical templating layer (CTL) concept. Unit cell thick, ferrimagnetic, binary Heusler compounds, have low magnetization and high perpendicular magnetic anisotropy in their tetragonally distorted forms, can sustain current driven DW motion in nanowire racetracks of -129 ms^-1 with the lowest current density to initiate motion of 2.8 10⁶ A cm^-2. The direction of the DW motion is determined by the bulk spin polarization of the Heusler. Moreover, the DW motion shows contribution by chiral spin orbit torques when studied under in-plane fields. We discuss the complex mechanism of the DW motion in Heusler films and identify a bulk Dzyaloshinskii-Moriya interaction and a spin Hall effect deriving from the CTLs.
One example of the extraordinary abilities of the Mn₃Z Heusler family, is shown by systematically tuning by an order of magnitude the bulk DMI field strength, by varying the composition of the Heusler alloy. These results are the first demonstration of DW motion in ultra-thin Heusler alloys with complex and tunable magnetic properties and is an important step to enable Heusler spintronics applications.