Skyrmions-based magnetic racetrack memory

Abstract

Magnetic skyrmions are topologically stable spin configurations with small size, which can be driven into motion by a small current. They are widely regarded as building blocks for next-generation magnetic storage. The main advantage of skyrmions lies in their particular dynamic behaviors, especially in their ability to move stably in racetrack under the action of small spin-polarized currents. The writing, driving and reading methods of skyrmions in racetrack are reviewed in detail in this paper, including the most recent research findings. The review focuses on the most commonly used driving method, i.e., driving skyrmions by applying spin-polarized currents. The clogging and annihilation of skyrmions in racetrack are analyzed, with the skyrmion Hall effect discussed which may lead skyrmion signals to lose. Methods to avoid skyrmion Hall effect are introduced and hence the optimized designs for skyrmion-based racetrack are also reviewed. Finally, some challenges of skyrmion-based racetrack memory are discussed.

A magnetic skyrmion diode based on potential well inducting effect

“…gates [15][16][17] and racetrack memories [18][19][20]. Some experiments have confirmed that skyrmions can be produced and driven by spin polarized currents at room temperature [21,22], indicating the enormous potential of using skyrmions in the next generation of spin electronic devices.…”

Skyrmion-based logic gates controlled by electric currents in synthetic antiferromagnet

“…[8,[12][13][14][15][16][17] Due to their nanosize, high mobility and topological protection, skyrmions can be regarded as the prominent binary data carrier in advanced memories, [18][19][20][21][22] logic gates and computing devices. [23][24][25] In particular, the presence of a skyrmion represents the data bit "1", while the absence of a skyrmion denotes the data bit "0". [26][27][28][29][30][31][32] Various ways have been proposed to realize the motion of skyrmions in a racetrack, [33][34][35][36] including the spinpolarized current, the temperature gradient, the magnetic anisotropy gradient, etc.…”

Realization of artificial skyrmion in CoCrPt/NiFe bilayers

“…[12,13] Skyrmion can be applied to the next-generation spintronics devices, such as racetrack memory and spin-transfer nanooscillators. [12,14,15] Skyrmion has been realized in the multilayer films at room temperature. [10,16,17] All these materials need a very strong Dzyaloshinskii-Moriya interaction (DMI).…”