Interfacial Dzyaloshinskii–Moriya interaction (DMI) is experimentally investigated in Pt/Co/Pt multilayer films under strain. A strong variation (from 0.1 to $0.8\mathrm{mJ}/{\mathrm{m}}^2$) of the DMI constant is demonstrated at $\pm 0.1\%$ in-plane uniaxial deformation of the films. The anisotropic strain induces strong DMI anisotropy. The DMI constant perpendicular to the strain direction changes sign, while the constant along the strain direction does not. Estimates show that the DMI can be controlled with an electric field in hybrid ferroelectric-ferromagnetic systems. So, the observed effect opens the way to control the DMI and eventually skyrmions with a voltage via a strain-mediated magnetoelectric coupling.

We report on results of computer micromodelling of antivortex states in asymmetrical crosslike ferromagnetic nanoparticles and their practical realization. The arrays of cobalt crosses with 1$\hskip0.3em${}$\mu${}m branches, 100 nm widths of the branches and 40 nm thicknesses, were fabricated using e-beam lithography and ion etching. Each branch of the cross was tapered at one end and bulbous at the other. The stable formation of antivortex magnetic states in these nanostructures during magnetization reversal was demonstrated experimentally using magnetic force microscopy.

We study the dependence of the Dzyaloshinskii-Moria interaction (DMI) using the $s\text{−}d$ model in the bilayer ferromagnet/heavy-metal system on the mechanical strain applied to the system. We show that DMI is sensitive to the strain perpendicular to the film plane. It can vary 40% under the strain of 0.3%. Such a strong variation is in agreement with recent experiment [ Phys. Rev. Lett. 124, 157202 (2020)]. The DMI coefficient variation is mostly related to the change of the distance between heavy-metal atomic planes under the strain. Changing the in-plane distance between the heavy-metal ions does not produce strong variation of DMI. Anisotropy of the DMI interaction may appear if the strain is anisotropic in the plane of the bilayer. The DMI anisotropy is related to the anisotropy of the electron effective mass in the film plane induced by the strain.

We report an experimental study of the optical properties of a two-dimensional square lattice of triangle Co and CoFe nanoparticles with a vortex magnetization distribution. We demonstrate that the intensity of light scattered in the diffraction maxima depends on the vorticity of the particles’ magnetization and can be manipulated by applying an external magnetic field. The experimental results can be understood in terms of simple phenomenological consideration.

We consider localized topologically nontrivial magnetic textures (skyrmions, antiskyrmions, and bimerons) in a thin magnetic film with anisotropic interfacial Dzyaloshinskii-Moriya interaction (iDMI). We use micromagnetic simulations and analytical consideration for studying the internal magnetic structure and stability of these textures. Skyrmion and antiskyrmion become elliptic and orient along the main axes of the iDMI tensor even for small anisotropy. In contrast, bimeron (antibimeron) orientation changes fluently with varying the iDMI anisotropy. Depending on the iDMI anisotropy the bimeron may consist of a vortex and antivortex pair or of “hedgehog” state and antivortex. In experiment the considered iDMI anisotropy can be induced by a strain applied to a magnetic film. We develop a phenomenological approach to establish the strain-iDMI relation.

The volt-ampere characteristics of a medium with helical magnetic structure are theoretically studied. Phenomenological and microscopic theories of a diode effect in such a medium are proposed. Diode effect appears only in the medium with noncoplanar magnetic structure. Two mechanisms for the diode effect are considered. They are electron energy spectrum asymmetry and electron scattering asymmetry.