Magnetic whirls in future data storage devices

Eurekalert  March 3, 2020 Researchers in Germany discovered that skyrmions and antiskyrmions are stabilized in different materials by a magnetic interaction that is directly tied to the structure of the host material. However, what was previously overlooked is that the magnetic dipoles also significantly interact with each other via their dipole-dipole interaction. This interaction always prefers skyrmions. For this reason, even “antiskyrmion materials” can exhibit skyrmions (but not vice versa). This happens preferably as the temperature is lowered. At a critical transition temperature, the two distinct objects coexist. The finding allows for an advanced version of the racetrack memory data […]

Skyrmions like it hot: Spin structures are controllable even at high temperatures

Nanowerk  February 13, 2020 When a skyrmion is driven by an electric current it propagates at skyrmion Hall angle (SkHA). This drive dependence, as well as thermal effects due to Joule heating, could be used to tailor skyrmion trajectories, but are not well understood. An international team of researchers (Germany, Belgium, USA – MIT, Czech Republic) had previously demonstrated the use of new spin structures for future magnetic storage devices. In their new research they report skyrmion dynamics as a function of temperature and drive amplitude. They found the skyrmion velocity depends strongly on temperature, while the skyrmion Hall angle […]

The first high-speed straight motion of magnetic skyrmions at room temperature demonstrated

Phys.org   November 19, 2019 The magnetic skyrmion can be driven by low current density and has a potential to be stabilized in nanoscale offering new directions of spintronics. However, there remain some fundamental issues in widely studied ferromagnetic systems which include a difficulty to realize stable ultra-small skyrmions at room temperature, presence of the skyrmion Hall effect, and limitation of velocity owing to the topological charge. Researchers in Japan have shown that skyrmion bubbles in a synthetic antiferromagnetic coupled multilayer are free from the above issues. Additive Dzyaloshinskii-Moriya interaction and spin-orbit torque (SOT) of the tailored stack allow stable skyrmion […]

A step towards probabilistic computing (w/video)

Eurekalert  May 14, 2019 In the search for new computer concepts, research is concentrating, amongst others, on probability-based computing. Researchers in Germany have succeeded in developing a material in which skyrmions can form. The researchers have also developed a method to exploit thermal diffusion of skyrmions in what is referred to as a reshuffler, a component of probability-based computing that automatically scrambles input data. The reshuffler produces a sequence with the same number of memory units but in a different order. Their probability has therefore remained the same. They have shown according to which laws diffusion occurs, its length and […]

Skyrmions could provide next generation data storage

Science Daily  April 1, 2019 Reconfigurable, ordered matter offers great potential for future low-power computer memory by storing information in energetically stable configurations. An international team of researchers (UK, USA – University of Colorado) describe stable, high-degree multi-skyrmion configurations where an arbitrary number of antiskyrmions are contained within a larger skyrmion called skyrmion bags. They have demonstrated the concept experimentally and numerically in liquid crystals and numerically in micromagnetic simulations either without or with magnetostatic effects. They found the skyrmion bags to act like single skyrmions in pairwise interaction and under the influence of current in magnetic materials. The finding […]

Taking magnetism for a spin: exploring the mysteries of skyrmions

Nanowerk  January 23, 2019 Until recently skyrmions were a phenomenon only observed at extreme low temperature. They need external magnetic fields to exist. A team of researchers in the US (Ames Laboratory, Oak Ridge National Laboratory, University of Florida) established a skyrmion lattice in a sample through exposure to magnetic fields and supercooling with liquid nitrogen. They were able to observe the skyrmion lattice in zero magnetic field, and then observe the decay of the skyrmions as the temperature warmed gaining critical new information about how skyrmions behave and how they revert to metastable state. The research provides a very solid […]

Controllable fast, tiny magnetic bits

Phys.org  January 4, 2019 Researchers at MIT present an analytical theory to describe three-dimensional magnetic textures in perpendicularly magnetized magnetic multilayers that arise in the presence of magnetostatic interactions and the Dzyaloshinskii-Moriya interaction (DMI). They demonstrated that domain walls in multilayers develop a complex twisted structure, which persists even for films with strong DMI. The origin of this twist is surface-volume stray field interactions that manifest as a depth-dependent effective field whose form mimics the DMI effective field. They found that the wall twist has a minor impact on the equilibrium skyrmion or domain size but can significantly affect current-driven […]

Magnetic antiparticles offer new horizons for information technologies

Eurekalert  August 15, 2018 An international team of researchers (Germany, Sweden, France, Czech Republic) theoretically explored the dynamics of skyrmions and antiskyrmions in ultrathin ferromagnetic films and showed that current-induced spin–orbit torques can lead to trochoidal motion and skyrmion–antiskyrmion pair generation, which occurs only for either the skyrmion or antiskyrmion, depending on the symmetry of the underlying Dzyaloshinskii–Moriya interaction. They developed algorithms which predict how spin–orbit torques can control the type of motion and the possibility to generate skyrmion lattices by antiskyrmion seeding. By increasing the amount of energy transferred to the system from the applied currents, they found that […]

Magnetic skyrmions: Not the only ones of their class

Eurekalert  June 28, 2018 Chiral bobber (ChBs) – which is characterized by several unique properties was predicted theoretically. An international team of researchers (Germany, Sweden, Russia, China) has demonstrated the existence of chiral bobbers in thin films of B20-type FeGe by means of quantitative off-axis electron holography. They showed that ChBs can coexist with skyrmions over a wide range of parameters, which suggests their possible practical applications in novel magnetic solid-state memory devices… read more. TECHNICAL ARTICLE 

A surprising twist on skyrmions

Phys.org  June 12, 2018 An international team of researchers (UK, China, Germany) measured the helicity angle of surface skyrmions, providing direct experimental evidence that a twisted skyrmion surface state also exists in bulk systems. The exact surface helicity angles of twisted skyrmions for both left- and right-handed chiral bulk Cu2OSeO3, in the single as well as in the multidomain skyrmion lattice state, are determined, revealing their detailed internal structure. The findings suggest that a skyrmion surface reconstruction is a universal phenomenon, stemming from the breaking of translational symmetry at the interface. The study suggests the importance of free surfaces has […]