Antiferromagnetic domain wall dynamics in rotating magnetic fields engineered by bending and twisting

We study domain wall motion in an intrinsically achiral helix-shaped antiferromagnet driven by a circularly polarized magnetic field, using the collective-variable approach and spin-lattice simulations. We show that this problem can be reduced to an effective dynamics of the domain wall in a rectilinear chiral biaxial antiferromagnet in the three rotating spatially-dependent fields. Two distinct modes of motion are identified: (i) rigid domain wall motion at low frequencies, characterized by constant velocity and a fixed domain wall phase; and (ii) oscillatory motion at high frequencies, accompanied by precessional dynamics of the domain wall. In the limit case of zero curvature, the domain wall becomes immobile; however, its phase remains fully synchronized with the external field, with the direction of phase rotation determined by the geometrical chirality of the helix. We predict that the domain wall velocity in the rigid mode can be efficiently tuned by both the field frequency and geometric manipulations via bending and twisting. These findings suggest that 3D curvilinear antiferromagnets such as helical structures may serve as a platform for the future high speed antiferromagnetic curvilinear spintronics applications.