Abstract
Searching for new methods controlling antiferromagnetic (AFM) domain wall is one of the most important issues for AFM spintronic device operation. In this work, we study theoretically the domain wall motion of an AFM nanowire, driven by the axial anisotropy gradient generated by external electric field, allowing the electro control of AFM domain wall motion in the merit of ultra-low energy loss. The domain wall velocity depending on the anisotropy gradient magnitude and intrinsic material properties is simulated based on the Landau-Lifshitz-Gilbert equation and also deduced using the energy dissipation theorem. It is found that the domain wall moves at a nearly constant velocity for small gradient, and accelerates for large gradient due to the enlarged domain wall width. The domain wall mobility is independent of lattice dimension and types of domain wall, while it is enhanced by the Dzyaloshinskii-Moriya interaction. In addition, the physical mechanism for much faster AFM wall dynamics than ferromagnetic wall dynamics is qualitatively explained. This work unveils a promising strategy for controlling the AFM domain walls, benefiting to future AFM spintronic applications.
Highlights
Nowadays, the interest in antiferromagnets increases significantly due to the promising application potentials of the so-called antiferromagnetic (AFM) spintronics [1,2]
The physical mechanism of the AFM wall dynamics being faster than FM wall dynamics is qualitatively explained
The domain wall velocity depending on the gradient magnitude and intrinsic physical parameters is simulated based on the LLG equation and calculated theoretically based on the energy dissipation theorem
Summary
The interest in antiferromagnets increases significantly due to the promising application potentials of the so-called antiferromagnetic (AFM) spintronics [1,2]. In CuMnAs [16] and Mn2Au [17] This speed is nearly two orders of magnitude larger than that for ferromagnetic (FM) domain wall motion typically, electric current control scheme will have high energy cost. Electric field controlled magnetic anisotropy has been experimentally revealed in magnetic heterostructures [20,21,22,23], and the anisotropy gradient can be obtained through an elaborate structure design such as wedged heterostructures [24] Under such a gradient, the AFM domain wall tends to move towards the low anisotropy side in order to reduce the free energy.
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