Current controlled random-access memory based on magnetic vortex handedness

Bohlens, Stellan; Krüger, Benjamin; Drews, André; Bolte, Markus; Meier, Guido; Pfannkuche, Daniela

doi:10.1063/1.2998584

Cited by 180 publications

(126 citation statements)

References 24 publications

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“…The investigation of dynamic behavior in ferromagnetic patterned elements is important in designing high-frequency memory elements [1,2], logic devices [3][4][5], and tunable magnonic filters [6,7]. Ferromagnetic rings are particularly interesting because they show a range of magnetic states at remanence such as the onion (or bi-domain) state, with two 180°domain walls (DWs), and the vortex (flux-closed) state, depending on the reversal process and the ring dimensions.…”

Section: Introductionmentioning

confidence: 99%

Comparative study of the ferromagnetic resonance behavior of coupled rectangular and circular Ni80Fe20rings

2014

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A systematic investigation of the dynamic behavior of Ni 80 Fe 20 ring arrays using broadband ferromagnetic resonance spectroscopy as a function of inter-ring spacing and ring thickness is presented. Four distinct resonance modes were found for rectangular rings compared to the two modes seen in circular rings of identical width due to the presence of sharp corners and nonuniform demagnetization field distribution. The resonance peaks were sensitive to the inter-ring spacing and the ring thickness due to magnetostatic coupling. Micromagnetic simulations and analytical calculations are compared with the experiment results.

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Section: Introductionmentioning

confidence: 99%

Comparative study of the ferromagnetic resonance behavior of coupled rectangular and circular Ni80Fe20rings

2014

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“…Thus far, both static and dynamic studies on the control of vortex structures have been primarily dedicated to manipulation of either the c or p alone. 8,[21][22][23][24][25][26][27][28][29][30][31] A few attempts have been made to control both c and p, but these attempts have been conducted without repetition, meaning that only a single event of control has been investigated. 32,33 Therefore, reliability and repeatability for control of both topological features has not yet been addressed.…”

Section: Introductionmentioning

confidence: 99%

Simultaneous control of magnetic topologies for reconfigurable vortex arrays

Fischer

Han

et al. 2017

NPG Asia Mater

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The topological spin textures in magnetic vortices in confined magnetic elements offer a platform for understanding the fundamental physics of nanoscale spin behavior and the potential of harnessing their unique spin structures for advanced magnetic technologies. For magnetic vortices to be practical, an effective reconfigurability of the two topologies of magnetic vortices, that is, the circularity and the polarity, is an essential prerequisite. The reconfiguration issue is highly relevant to the question of whether both circularity and polarity are reliably and efficiently controllable. In this work, we report the first direct observation of simultaneous control of both circularity and polarity by the sole application of an in-plane magnetic field to arrays of asymmetrically shaped permalloy disks. Our investigation demonstrates that a high degree of reliability for control of both topologies can be achieved by tailoring the geometry of the disk arrays. We also propose a new approach to control the vortex structures by manipulating the effect of the stray field on the dynamics of vortex creation. The current study is expected to facilitate complete and effective reconfiguration of magnetic vortex structures, thereby enhancing the prospects for technological applications of magnetic vortices.

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“…Each of these quantities can be potentially used for storing of a bit of information in a high-speed magnetic random access memory. [5] In this respect the possibility of controllable manipulating of the chirality and polarity values is crucial one. Though a number of mechanisms of controllable vortex polarity switching are already proposed, [6][7][8][9] the controllable vortex chirality switching is still a challenging problem because it requires a fine asymmetrical tuning the nanoscale system: the asymmetry must be introduced into geometry of the nanomagnet [10] or into the spatial distribution of the applied magnetic fields.…”

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confidence: 99%

Controllable vortex chirality switching on spherical shells

Yershov

Kravchuk

Sheka

et al. 2015

Journal of Applied Physics

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A simple mechanism of controllable switching of magnetic vortex chirality is proposed. We consider curvilinear magnetic nanoshells of spherical geometry whose ground state is a vortex magnetization distribution. Chirality of this magnetic vortex can be switched in controllable way by applying a Gaussian pulse of spatially uniform magnetic field along the symmetry axis of the shell. The chirality switching process is explored in detail numerically for various parameters of magnetic pulse: the corresponding switching diagram is build. The role of the curvature is ascertained by studying the switching diagram evolution under the continuous transition from hemispherical shell to the disk shaped sample with the volume and thickness kept constant. Magnetic vortex has two binary characteristics: chirality C = ±1, the counterclockwise (C = +1) or clockwise (C = −1) direction of magnetization circulation; and polarity p = ±1, the up (p = +1) or down (p = −1) direction of the vortex core magnetization. Each of these quantities can be potentially used for storing of a bit of information in a high-speed magnetic random access memory. [5] In this respect the possibility of controllable manipulating of the chirality and polarity values is crucial one. Though a number of mechanisms of controllable vortex polarity switching are already proposed, [6][7][8][9] the controllable vortex chirality switching is still a challenging problem because it requires a fine asymmetrical tuning the nanoscale system: the asymmetry must be introduced into geometry of the nanomagnet [10] or into the spatial distribution of the applied magnetic fields. [11] In symmetrical planar systems e.g. magnetic nanodisks, the vortex chirality control requires highly accurate setting of parameters of the of magnetic field pulse[12] or spin-current pulse.[13]Here we propose a simple mechanism of vortex chirality control for a symmetrical system by using a simple spatially uniform pulse of magnetic field. The idea is to proceed from planar to curvilinear magnetic shells with spherical geometry, see Fig. 1. We choose the magnetic pulse with the Gaussian temporal profile B = −e z B 0 exp[−(t − 3τ ) 2 /τ 2 ], where B 0 and τ are ampli- tude and width of the field pulse respectively. The pulse is applied along the symmetry axis of the system, B||e z . Note, that recently we reported on the vortex polarity switching for spherical shells under action of the same Gaussian field pulse applied within the xy-plane [14].To study the magnetization dynamics induced by the field pulse we perform numerical simulation of the Landau-Lifshitz equation using the NMAG code. [15] We start from the hemispherical shell, see Fig. 1 with inner radius R 0 = 100 nm, radial thickness h = 10 nm and material parameters of Permalloy (Ni 80 Fe 20 ), namely the saturation magnetization M s = 7.96×10 5 A/m, exchange constant A = 1.3 × 10 −11 J/m, anisotropy is neglected, and damping coefficient α = 0.01. The chosen material parameters result in characteristic length scale of the system, an excha...

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Current controlled random-access memory based on magnetic vortex handedness

Cited by 180 publications

References 24 publications

Comparative study of the ferromagnetic resonance behavior of coupled rectangular and circular Ni80Fe20rings

Comparative study of the ferromagnetic resonance behavior of coupled rectangular and circular Ni80Fe20rings

Simultaneous control of magnetic topologies for reconfigurable vortex arrays

Controllable vortex chirality switching on spherical shells

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