Magnetization in narrow ribbons: curvature effects

A ribbon is a surface swept out by a line segment turning as it moves along a central curve. For narrow magnetic ribbons, for which the length of the line segment is much less than the length of the curve, the anisotropy induced by the magnetostatic interaction is biaxial, with…

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Magnetism in curved geometries

Extending planar two-dimensional structures into the three-dimensional space has become a general trend in multiple disciplines, including electronics, photonics, plasmonics and magnetics. This approach provides means to modify conventional or to launch novel functionalities by tailoring the geometry of an object, e.g. its local curvature. In a generic electronic system,…

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Rashba Torque Driven Domain Wall Motion in Magnetic Helices

Manipulation of the domain wall propagation in magnetic wires is a key practical task for a number of devices including racetrack memory and magnetic logic. Recently, curvilinear effects emerged as an efficient mean to impact substantially the statics and dynamics of magnetic textures. Here, we demonstrate that the curvilinear form of the exchange…

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Curvature and torsion effects in spin-current driven domain wall motion

The domain wall motion along a helix-shaped nanowire is studied for the case of spin-current driving via the Zhang-Li mechanism. The analysis is based on the collective variable approach. Two effects are ascertained: (i) the curvature results in the appearance of the Walker limit for a uniaxial wire, and (ii)…

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Curvature-induced domain wall pinning

A local bend of a nanowire is a source of pinning potential for a transversal head-to-head (tail-to-tail) domain wall. Eigenfrequency of the domain wall free oscillations at the pinning potential and the effective friction are determined as functions of the curvature and domain wall width. The pinning potential originates from…

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Torsion-induced effects in magnetic nanowires

A magnetic helix wire is one of the simplest magnetic systems which manifests properties of both curvature and torsion. Possible equilibrium magnetization states in the helix wire with different anisotropy directions are studied theoretically. There exist two equilibrium states in the helix wire with easy-tangential anisotropy: a quasitangential magnetization distribution…

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Spin-polarized Current and Ørsted Field

A spin-polarized electrical current leads to a variety of periodical magnetic structures in nanostripes. In the presence of the Ørsted field, which always assists an electrical current, the basic types of magnetic structures, i.e., a vortex-antivortex crystal and cross-tie domain walls, survive. The Ørsted field prevents saturation of the nanostripe…

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Möbius Ring: Magnetic and Geometrical Chiralities

Chirality symmetry breaking is a common phenomenon in the Nature. The most intriguing examples come from life sciences (chirality symmetry breaking of biological macromolecules, such as DNA) and from particle physics (e.g. neutrino helicity symmetry breaking). In magnetism, chirality is a characteristic of a number of topologically nontrivial structures, such…

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Vortex polarity switching in magnets with surface anisotropy

Vortex core reversal in magnetic particle is essentially influenced by a surface anisotropy. Under the action of a perpendicular static magnetic field the vortex core undergoes a shape deformation of pillow- or barrel-shaped type, depending on the type of the surface anisotropy. This deformation plays a key point in the…

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Curvature effects in statics and dynamics of low dimensional magnets

Nowadays there is a growing interest in studying of topological structures in curved magnetic objects such as magnetic nanowires and nanoshells. We develop an approach to treat magnetic energy of a ferromagnet for arbitrary curved wires and shells on the assumption that the anisotropy contribution greatly exceeds the dipolar and…

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