Abstract:Nanoscale topologically nontrivial spin textures, such as magnetic skyrmions, have been identified as promising candidates for the transport and storage of information for spintronic applications, notably magnetic racetrack memory devices. The design and realization of a single skyrmion chain at room temperature (RT) and above in the low-dimensional nanostructures are of great importance for future practical applications. Here, we report the creation of a single skyrmion bubble chain in a geometrically confine… Show more
“…This result is very interesting as here our model utilizes another mechanism, i.e. a weak exchange interaction between the FM and AFM films, so that neither a strong perpendicular anisotropy, nor a high exchange energy, nor an applied field are required to obtain skyrmions, while at least one of them is usually necessary 2,14,40,41 .Figure 5( a ) Phase diagrams of the magnetic moment distribution as functions of the DMI constant D (in mJ/m 2 ), and saturation magnetization M S (in MA/m) of the ferromagnetic film, for A i = 10.8 mJ/m 2 , under zero field. ( b ) Magnetic pattern distribution among the six atomic layers, for A i = 10.8 mJ/m 2 , D = 4.0 mJ/m 2 and M S = 1.0 MA/m.…”
Section: Resultsmentioning
confidence: 94%
“…In the cases with a low M S and a very high D , under zero field, only stripe domains are formed, whereas clusters of eight and twelve regular skyrmions occur under H = 1.5 and 2.0 T, respectively. It should be mentioned that skyrmions in most chiral magnets were derived from stripe domains by external field 2,14,40,41 . Here, we have shown that skyrmions can be induced in a non-chiral FM film with the help of an exchange-coupled chiral AFM film.…”
Magnetic skyrmions are topologically protected domain structures related to the Dzyaloshinskii-Moriya interaction (DMI). To understand how magnetic skyrmions occur under different circumstances, we propose a model for skyrmion formation in a bilayer system of ferromagnetic/antiferromagnetic (FM/AFM) films, in which the bulk DMI is only present in the AFM film. Micromagnetic simulations reveal that skyrmions are formed in this system due to the competition between the DMI and demagnetization energies. A critical interfacial exchange energy (
A
i
= 6.5 mJ/m
2
) is determined, above which the competition occurs at its full extent. More skyrmions are formed with increasing external magnetic field till a critical value above which the external field is too large and thus leading to the annihilation of skyrmions. The spacing between two skyrmions can be as small as 45 nm. Our results may give technological implications for future skyrmion applications.
“…This result is very interesting as here our model utilizes another mechanism, i.e. a weak exchange interaction between the FM and AFM films, so that neither a strong perpendicular anisotropy, nor a high exchange energy, nor an applied field are required to obtain skyrmions, while at least one of them is usually necessary 2,14,40,41 .Figure 5( a ) Phase diagrams of the magnetic moment distribution as functions of the DMI constant D (in mJ/m 2 ), and saturation magnetization M S (in MA/m) of the ferromagnetic film, for A i = 10.8 mJ/m 2 , under zero field. ( b ) Magnetic pattern distribution among the six atomic layers, for A i = 10.8 mJ/m 2 , D = 4.0 mJ/m 2 and M S = 1.0 MA/m.…”
Section: Resultsmentioning
confidence: 94%
“…In the cases with a low M S and a very high D , under zero field, only stripe domains are formed, whereas clusters of eight and twelve regular skyrmions occur under H = 1.5 and 2.0 T, respectively. It should be mentioned that skyrmions in most chiral magnets were derived from stripe domains by external field 2,14,40,41 . Here, we have shown that skyrmions can be induced in a non-chiral FM film with the help of an exchange-coupled chiral AFM film.…”
Magnetic skyrmions are topologically protected domain structures related to the Dzyaloshinskii-Moriya interaction (DMI). To understand how magnetic skyrmions occur under different circumstances, we propose a model for skyrmion formation in a bilayer system of ferromagnetic/antiferromagnetic (FM/AFM) films, in which the bulk DMI is only present in the AFM film. Micromagnetic simulations reveal that skyrmions are formed in this system due to the competition between the DMI and demagnetization energies. A critical interfacial exchange energy (
A
i
= 6.5 mJ/m
2
) is determined, above which the competition occurs at its full extent. More skyrmions are formed with increasing external magnetic field till a critical value above which the external field is too large and thus leading to the annihilation of skyrmions. The spacing between two skyrmions can be as small as 45 nm. Our results may give technological implications for future skyrmion applications.
“…SKBs are topologically equivalent to magnetic skyrmions and exhibit similar topological properties, such as the topological Hall effect, 27 skyrmion Hall effect, 33 and ultra-low driving current density for current-induced motion. 25 More importantly, SKBs show a significantly high thermal stability over a wide temperature range crossing room temperature, 27,28,34 showing a high potential of SKBs for the construction of memory devices.Contrary to DMI-stabilized skyrmions with a fixed helicity, SKBs in centrosymmetric magnets possess two degrees of freedom, i.e., vorticity and helicity, 35 which makes them usually coexist with the topologically trivial bubbles (topological number is equal to 0), [28][29][30][31]37 or exhibit multiple topologies such as biskyrmions, 25,27,30,36 and various metastable SKBs 28,30,36 (for example, pendulum-shaped SKBs 29 and bifurcation-shaped SKBs 28,30,36 ).When external stimuli, such as magnetic field H or spin-polarized current, are applied, the spin structures of the trivial and metastable SKBs may vary with the motion of Bloch lines (BLs), making them unsuitable for the application in magnetic racetrack memory devices.Therefore, in order to be suitable for such applications, it is essential to remove trivial bubbles and metastable SKBs. 21Recent theoretical simulations, based on the nanostructured frustrated magnet, showed that the periodically modulated spin textures at geometrical boundaries had a significant influence on the magnetization dynamics of SKBs , 35 offering a new path that designing proper…”
mentioning
confidence: 99%
“…SKBs are topologically equivalent to magnetic skyrmions and exhibit similar topological properties, such as the topological Hall effect, 27 skyrmion Hall effect, 33 and ultra-low driving current density for current-induced motion. 25 More importantly, SKBs show a significantly high thermal stability over a wide temperature range crossing room temperature, 27,28,34 showing a high potential of SKBs for the construction of memory devices.…”
The discovery of magnetic skyrmion bubbles in centrosymmetric magnets has been receiving increasing interest from the research community, due to the fascinating physics of topological spin textures and its possible applications to spintronics. However, key challenges remain, such as how to manipulate the nucleation of skyrmion bubbles to exclude the trivial bubbles or metastable skyrmion bubbles that usually coexist with skyrmion bubbles in the centrosymmetric magnets. Here, we report having successfully performed this task by applying spatially geometric confinement to a centrosymmetric frustrated Fe 3 Sn 2 magnet. We demonstrate that the spatially geometric confinement can indeed stabilize the skyrmion bubbles, by effectively suppressing the formation of trivial bubbles and metastable skyrmion bubbles. We also show that the critical magnetic field for the nucleation of the skyrmion bubbles in the confined Fe 3 Sn 2 nanostripes is drastically less, by an order of magnitude, than that what is required in the thin plate without geometrical confinement. By analyzing how the width and thickness of the nanostripes affect the spin textures of skyrmion bubbles, we infer that the topological transition of skyrmion bubbles is closely related to the dipole-dipole interaction, which we find is consistent with theoretical simulations. The results presented here represent an important step forward in manipulating the topological spin textures of skyrmion bubbles, making us closer to achieving the fabrication of skyrmion-based racetrack memory devices.Magnetic skyrmions are topologically protected vortex-like objects that were first discovered in the chiral, non-centrosymmetric magnets 1-6 where they are stabilized by the Dzyaloshinskii-Moriya interaction (DMI). Unlike the conventional, "rigid" magnetic domain walls, they are flexible in shape-deformation to avoid pinning centres, 7,8 and therefore only an ultra-low current density is needed to drive them to move. 7-12 This fascinating topological property, combined with their nanoscale size and stable particle-like features make skyrmions promising candidate for carrying magnetic information in further high-density and low-power consumption spintronic devices based on the racetrack memory concept. 8,13,[14][15][16][17][18][19][20][21][22][23][24] Recent studies showed that some non-chiral centrosymmetric magnets could host skyrmion bubbles (SKBs), 25-32 stabilized by the interplay of the external magnetic field, ferromagnetic exchange interaction, uniaxial magnetic anisotropy, and dipole-dipole interaction (DDI). SKBs are topologically equivalent to magnetic skyrmions and exhibit similar topological properties, such as the topological Hall effect, 27 skyrmion Hall effect, 33 and ultra-low driving current density for current-induced motion. 25 More importantly, SKBs show a significantly high thermal stability over a wide temperature range crossing room temperature, 27,28,34 showing a high potential of SKBs for the construction of memory devices.Contrary to DMI-stabilized skyr...
“…[22] Moreover, single-chain skyrmion bubbles in 600 nm nanostripes were reported to be stable far above the room temperature, up to 630 K, thus making significant progress toward nanoscale skyrmion -based spintronic. [23] On the other hand, it is also of interest to manipulate skyrmionic textures by thermal gradients in magnetic nanodevices. [24][25][26] In this paper we show first evidence of the room-temperature skyrmion detection by thermopower in Fe 3 Sn 2 in a simple thermal gradient and discuss relevant mechanism.…”
We present the room-temperature thermoelectric signature of skyrmion bubbles. This is observed in Fe 3 Sn 2 , a Kagome Dirac crystal with massive Dirac fermions that features a high-temperature skyrmion phase. The room-temperature skyrmion bubbles show magnetic-field dependence of the wavevector whereas the thermopower is dominated by the electronic diffusion mechanism, allowing for the skyrmionic bubble detection. The results pave the way for future skyrmion-based devices based on the manipulation of the thermal gradient.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
