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A publication with Jairo Sinova on the role of magnetic dipolar interactions in skyrmion lattices has been publised in Newton.

Magnetic skyrmions are topological two-dimensional (2D) spin textures that can be stabilized at room temperature and low magnetic fields in magnetic multilayer stacks. Besides their envisioned applications in data storage and processing, these 2D quasiparticles constitute an ideal model system to study 2D particle properties. More precisely, the role of inter-particle dipolar interactions in 2D ensembles can be fully captured in skyrmion lattices. We engineer a multilayer stack hosting skyrmion lattices and increase the relevance of the dipolar coupling by increasing the number of repetitions n from to . To ascertain the impact on the spin structure, we carry out a series of imaging experiments and find a drastic change of the skyrmion size. We develop an analytical description for the skyrmion radius in the whole multilayer regime, from thin to thick film limits, identifying the key impact of the nucleation process leading to the skyrmion lattice. Our work provides a detailed understanding of the skyrmion-skyrmion interaction, clarifying the role of dipolar interactions as the multilayer stack is expanded in the z direction.

A publication with Jairo Sinova and Olena Gomonay on Curvature-Induced Magnetization of Altermagnetic Films has been publised in Physical Review Letters.

The altermagnetic nature of a large class of magnetically ordered materials is the source of a wide range of new effects. Here, we show that the merging of two areas, namely the altermagnetism and the physics of curvilinear low-dimensional magnets gives rise to a distinct novel physical effect: a curvature-induced magnetization in bend altermagnetic films. This effect opens a promising possibility for imaging of the domain structure in the magnetically compensated structures. We consider a thin film of a -wave altermagnet bent in a stretching-free manner and demonstrate that gradients of the film curvature induce a local magnetization that is approximately tangential to the film. The magnetization amplitude directly reflects the altermagnetic symmetry and depends on the direction of bending. It is maximal for the bending along directions of the maximal altermagnetic splitting of the magnon bands. A periodically bent film of sinusoidal shape possesses a total magnetic moment per period ∝2⁢4, where and are the bending amplitude and wave vector, respectively. The total magnetic moment is perpendicular to the plane of the unbent film and its direction (up or down) is determined by the bending direction. A film roll-up to a nanotube possesses a toroidal moment directed along the tube ∝/2 per one coil, where and are the coil radius and the pitch between coils. All these analytical predictions agree with numerical spin-lattice simulations.

A publication with Ricardo Zarzuela, Rodrigo Jaeschke-Ubiergo, Olena Gomonay, Libor Šmejkal and Jairo Sinova on the transport theory and spin-transfer physics in -wave altermagnets has been publised in Physical Review B.

We develop a mesoscale transport theory for the charge and spin degrees of freedom of itinerant carriers in a -wave altermagnet. Our effective Lagrangian description is built on the slave-boson formulation of the microscopic − model. We obtain a spin-polarized diffusive contribution to the effective Hamiltonian, which has no counterpart in conventional antiferromagnetism and is parametrized by the spin splitting, responsible for the so-called spin-splitter effect in -wave altermagnets. We also elucidate the spin-transfer response of the itinerant fluid as well as the spin pumping into the altermagnet, which exhibit previously unidentified combinations of the charge current and spatial partial derivatives (namely, {,} and {,}). The emergent spin-transfer physics in -wave altermagnets opens up promising perspectives for the dynamics of spin textures, such as the domain-wall motion driven by transverse charge currents. Additionally, we consider the effect of elastic distortions on the aforementioned transport properties.

A publication with Jairo Sinova, Libor Šmejkal and Olena Gomonay on altermagnetic variants in thin films of M⁢n5⁢S⁢i3 has been publised in Physical Review B.

The altermagnet candidate M⁢n5⁢S⁢i3 has attracted wide attention in the context of nonrelativistic spin physics, due to its composition of light elements. In this study, we demonstrate a hallmark of altermagnetism in M⁢n5⁢S⁢i3 thin films, namely the three options, or variants, for the checkerboard distribution of the magnetic Mn atoms. The magnetic symmetries were altered by field-rotation of the Néel vector along relevant crystal directions, resulting in anomalous Hall effect anisotropy. The experimental results in nanoscale devices were corroborated by a theoretical model involving atomic site dependent anisotropy and bulk Dzyaloshinskii-Moriya interaction for a single variant. These findings elevate M⁢n5⁢S⁢i3 from a candidate to a proven altermagnet.

A publication with Olena Gomonay, VK Bharadwaj and Tobias Wagner on antiferromagnetic vortex states in NiO-Fe nanostructures has been publised in Advanced Materials Interfaces.

Magnetic vortices are topological spin structures frequently found in ferromagnets, yet novel to antiferromagnets. By combining experiment and theory, it is demonstrated that in a nanostructured antiferromagnetic-ferromagnetic NiO(111)-Fe(110) bilayer, a magnetic vortex is naturally stabilized by magnetostatic interactions in the ferromagnet and is imprinted onto the adjacent antiferromagnet via interface exchange coupling. Micromagnetic simulations are used to construct a corresponding phase diagram of the stability of the imprinted antiferromagnetic vortex state. The in-depth analysis reveals that the interplay between interface exchange coupling and the antiferromagnet magnetic anisotropy plays a crucial role in locally reorienting the Néel vector out-of-plane in the prototypical in-plane antiferromagnet NiO and thereby stabilizing the vortices in the antiferromagnet.