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Roman Teslia

Publications and source records attributed to Roman Teslia.

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Current- and field-driven domain wall dynamics and chirality switching in a planar helimagnet

We study the effect of electric current and magnetic field on the dynamics of chirality in a helimagnet with a strong easy-plane anisotropy. Using a continuum theory, derived for a quasi-one-dimensional frustrated ferromagnet close to the Lifshitz point, we show that a domain wall connecting domains with opposite chiralities can be driven by the current via the dissipative (non-adiabatic) component of the spin-transfer torque. Further, it is demonstrated that the adiabatic part of the torque in the presence of a magnetic field breaks the symmetry of the effective magnetic potential energy with respect to the chirality. We show that the leading symmetry-breaking term arises in the third order in the magnetization gradient, and derive the conditions of the chirality switching. Our conclusions are supported by numerical spin-lattice simulations.

cond-mat.mes-hall

Current-controlled chirality dynamics in a mesoscopic magnetic domain wall

Chirality as internal degree of freedom of a mesoscopic domain wall inside a quasi-one-dimensional fixture can be controlled by spin-polarized current for ferro- as well as anti-ferro-magnetic domain walls. We show that the current density required for the chirality manipulation can be significantly reduced in the low-temperature regime where the chirality dynamics exhibits quantum effects. In this quantum regime, weak currents can excite Bloch oscillations of the domain wall angular rotation velocity, with the oscillation frequency proportional to the current, modulated by a much higher magnon-range frequency. In addition to that, the Wannier-Stark localization effects enable controlled switching between different chiral states, suppressing inertial effects characteristic for the classical regime. We also show that for recently discovered novel class of magnetic materials -- altermagnets -- chirality switching can be driven by the usual charge current (not spin-polarized).

cond-mat.mes-hall