Micromagnetic Theory of Curvilinear Ferromagnetic Shells

The concept of curvature and chirality in space and time are foundational for the understanding of the organic life and formation of matter in the Universe. Chiral interactions but also curvature effects are tacitly accepted to be local. A prototypical condensed matter example is a local spin-orbit- or curvature-induced Rashba…

Continue reading

Unidirectional tilt of domain walls in equilibrium in biaxial stripes with Dzyaloshinskii–Moriya interaction

The orientation of a chiral magnetic domain wall in a racetrack determines its dynamical properties. In equilibrium, magnetic domain walls are expected to be oriented perpendicular to the stripe axis. We demonstrate the appearance of a unidirectional domain wall tilt in out-of-plane magnetized stripes with biaxial anisotropy and Dzyaloshinskii-Moriya interaction…

Continue reading

Domain wall diode based on functionally graded Dzyaloshinskii-Moriya interaction

Domain wall diode

We present a general approach for studying the dynamics of domain walls in biaxial ferromagnetic stripes with functionally graded Dzyaloshinskii–Moriya interaction (DMI). By engineering the spatial profile of the DMI parameter, we propose the concept of a diode, which implements the filtering of domain walls of a certain topological charge…

Continue reading

Spontaneous deformation of flexible ferromagnetic ribbons induced by Dzyaloshinskii-Moriya interaction

Here, we predict the effect of the spontaneous deformation of a flexible ferromagnetic ribbon induced by Dzyaloshinskii-Moriya interaction (DMI). The geometrical form of the deformation is determined both by the type of DMI and by the equilibrium magnetization of the stripe. We found three different geometrical phases, namely, (i) the…

Continue reading

Spin eigenexcitations of an antiferromagnetic skyrmion

We study spin eigenexcitation of a skyrmion in a collinear uniaxial antiferromagnet by means of analytical and numerical methods. We found a discrete spectrum of modes which are localized on the skyrmion. Based on a qualitatively different dependence of the mode eigenfrequencies on the skyrmion radius R0, we divided all…

Continue reading

Curvature induced magnonic crystal in nanowires

A new type of magnonic crystals, curvature induced ones, is realized in ferromagnetic nanowires with periodically deformed shape. A magnon band structure of such crystal is fully determined by its curvature: the developed theory is well confirmed by simulations. An application to nanoscale spintronic devises with the geometrically tunable parameters…

Continue reading

Прощання з Юрієм Борисовичем Гайдідеєм

30 жовтня пішов з життя видатний фізик-теоретик, доктор фіз.-мат. наук, професор Юрій Борисович Гайдідей Колектив Інституту теоретичної фізики ім. М.М. Боголюбова НАН України, колектив групи RiTM глибоко сумують з приводу непоправної втрати і висловлюють щирі співчуття рідним і близьким покійного. Кремація відбудеться на Байковому цвинтарі 1 листопада о 12 годині…

Continue reading

Shape transformations in flexible magnetic rings

The development of motility mechanisms controllable on the sub-micron length scale is crucial for both nanorobotics and shapeable magnetoelectronics. We showcase that the nanoscale shape deformation of a flexible magnet can be controlled by its magnetic attributes. Namely, we consider a problem of coupling the geometrical and magnetic degrees of…

Continue reading

Chiral Skyrmion and Skyrmionium States Engineered by the Gradient of Curvature

Curvilinear nanomagnets can support magnetic skyrmions stabilized at a local curvature without any intrinsic chiral interactions. Here, we propose an alternative mechanism to stabilize chiral Néel skyrmion states relying on the gradient of curvature. We illustrate our approach with an example of a magnetic thin film with perpendicular magnetic anisotropy…

Continue reading