Dynamics of skyrmion spin states confirmed in neutron-scattering experiments

Phys.org.  November 11, 2023 Some magnetic systems feature spin textures, real-space patterns in the orientation of spins that can topologically form non-trivial configurations. Among them, a vortex-like spin swirling texture known as a magnetic skyrmion has attracted particular attention. Lattices of skyrmions form in the helimagnet MnSi with a periodicity of 18 nm, which makes them amenable to investigation by Lorentz transmission electron microscopy in real space and by small-angle neutron scattering in momentum space. An international team of researchers (Japan, France, Sweden, Czech Republic) examined the low-energy excitations of the skyrmion state in MnSi by using the neutron spin-echo technique […]

Imaging the elusive skyrmion: Neutron tomography reveals their shapes and dynamics in bulk materials

Phys.org   September 26, 2023 Commonly observed in thin systems as two-dimensional sheets, in three dimensions skyrmions form tubes that are thought to nucleate and annihilate along their depth on points of vanishing magnetization. However, a lack of techniques that can probe the bulk of the material has made it difficult to perform experimental visualizations of skyrmion lattices and their stabilization through defects. An international team of researchers ( Canada, USA – NIST, SUNY Buffalo, Germany) provided three-dimensional visualizations of a bulk Co8Zn8Mn4 skyrmion lattice through a tomographic algorithm applied to multiprojection small-angle neutron scattering measurements. Reconstructions of the sample showed […]

Generating biskyrmions in a rare earth magnet

Phys.org  September 16, 2023 The low stability of most magnetic skyrmions leads to either a narrow temperature range in which they can exist, a low density of skyrmions, or the need for an external magnetic field, which greatly limits their wide application. An international team of researchers (USA – NIST, Japan, South Korea) has reported real-space imaging of a two-dimensional skyrmion lattice in a thin film of Fe0.5Co0.5Si using Lorentz transmission electron microscopy. With a magnetic field of 50–70 mT applied normal to the film, they observed skyrmions in the form of a hexagonal arrangement of swirling spin textures, with a […]

The transformation between different topological spin textures

Phys.org  November 11, 2022 Skyrmions and bimerons are versatile topological spin textures that can be used as information bits for both classical and quantum computing. An international team of researchers (Japan, China, Australia) has demonstrated the creation of isolated skyrmions and their subsequent transformation to bimerons by harnessing the electric current-induced Oersted field and temperature-induced perpendicular magnetic anisotropy variation. The reversible transformation between skyrmions and bimerons was controlled by the current amplitude and scanning direction. Both skyrmions and bimerons could be created in the same system through the skyrmion-bimeron transformation and magnetization switching. Deformed skyrmion bubbles and chiral labyrinth domains […]

Magnetic skyrmions: Two methods for creating them and guiding their motion

Phys.org  September 7, 2022 Magnetic skyrmions are envisioned as information carriers in future information technology. Skyrmions in thin magnetic films may act as an ideal test bed to study the dynamics of topologically non-trivial magnetic quasi-particles. To study the skyrmions reliable generation of the magnetic skyrmion at controlled positions is required. An international team of researchers (Germany, the Netherlands) developed full nanometer-scale control of the skyrmion generation by two independent approaches employing He+-ion irradiation or using backside reflective masks. The influence of nanopatterned backside aluminum masks on the optical excitation was studied in two sample geometries with varying layer sequence […]

Unlocking the recipe for designer magnetic particles for next generation computing technologies

Phys.org   August 4, 2022 Recently ensembles of chiral spin textures, consisting of skyrmions and magnetic stripes, are shown to possess rich interactions with potential for device applications. However, several fundamental aspects of chiral spin texture phenomenology remain to be elucidated, including their domain wall (DW) structure, thermodynamic stability, and morphological transitions. An international team of researchers (Singapore, USA – Lawrence Berkeley National Laboratory) has shown the evolution of these textural characteristics unveiled on a tunable multilayer platform using a combination of full-field electron and soft X-ray microscopies with numerical simulations. They demonstrated the increasing chiral interactions, the emergence of Néel […]

Researchers create exotic magnetic structures with laser light

Phys.org  April 25, 2022 To interface skyrmionics with electronic devices requires efficient and reliable ways of creating and destroying such excitations. An international team of researchers (Germany, USA – Flatiron Institute, Sweden) unravel the microscopic mechanism behind ultrafast skyrmion generation by femtosecond laser pulses in transition metal thin films. They employed a theoretical approach based on a two-band electronic model and showed that by exciting the itinerant electronic subsystem with a femtosecond laser ultrafast skyrmion nucleation can occur on a 100 fs timescale. By combining numerical simulations with an analytical treatment, they identified the coupling between electronic currents and the […]

Scientists successfully manipulate a single skyrmion at room temperature

Nanowerk  December 17, 2021 The key to creating spintronics devices is the ability to effectively manipulate, and measure, a single skyrmion. Researchers in Japan used a thin magnetic plate made up of a compound of cobalt, zinc, and manganese, Co9Zn9Mn2 to observe the dynamics of a single skyrmion at room temperature. They were able to track the motions of the skyrmion and control its Hall motion directions by flipping the magnetic field when they subjected it to ultrafast pulses of electric current—on the scale of nanoseconds. They found that the skyrmion’s motion demonstrated a dynamic transition from a pinned static […]

By keeping ferroelectric ‘bubbles’ intact, researchers pave way for new devices

Phys.org  November 19, 2021 Bubble-like domains, typically a precursor to the electrical skyrmions, arise in ultrathin complex oxide ferroelectric–dielectric–ferroelectric heterostructures epitaxially clamped with flat substrates. An international team of researchers (USA – Argonne National Laboratory, University of Arkansas, University of Chicago, Australia) peeled off heterostructure thin films containing electrical bubbles from the substrate, while keeping them fully intact. To establish that the bubble domains remained intact, they measured the capacitance and piezoelectric properties and found they stayed relatively stable up to a high voltage. The combination of experiment and simulation proved conclusively that these bubbles can live even when removed […]

Scientists successfully manipulate a single skyrmion at room temperature

Nanowerk  November 24, 2021 The key to creating spintronics devices is the ability to effectively manipulate, and measure, a single tiny vortex. Researchers in Japan used a thin magnetic plate made up of a compound of cobalt, zinc, and manganese which is known as a chiral-lattice magnet. They directly observed the dynamics of a single skyrmion at room temperature and tracked the motions of the skyrmion and control its Hall motion directions by flipping the magnetic field when they subjected it to ultrafast pulses of electric current—on the scale of nanoseconds. They found that the skyrmion’s motion demonstrated a dynamic […]