Properties of magnetic nanodots with perpendicular anisotropy

Novais, E.; Landeros, P.; Barbosa, A. G. S.; Martins, Maximiliano; García, F.; Guimarães, A.P.

doi:10.1063/1.3631081

Cited by 24 publications

(22 citation statements)

References 33 publications

(62 reference statements)

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“…In this sense the influence of perpendicular uniaxial anisotropy (PUA) and in-plane uniaxial anisotropy (IPUA) in the magnetization process of magnetic vortices has gained interest in recent years. [13][14][15][16][17][18][19] In multilayer systems a perpendicular uniaxial anisotropy (PUA) can be induced varying the substrate thickness 18 , while IPUA can be induced through inverse magnetostriction effect by voltage-induced strain via a PZT piezoelectric transducer 14,20 . The IPUA allows real-time control of the eigefrequency in an appreciable range 13 .…”

Section: Introductionmentioning

confidence: 99%

Controlling energy transfer time between two coupled magnetic vortex-state disks

Vigo-Cotrina

Guimarães

2016

Journal of Applied Physics

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The influence of the in-plane uniaxial anisotropy (IPUA) in the mutual energy transfer time (τ ) between two identical coupled nanodisks was studied. Using an analytical dipolar model we obtained the interactions between the disks along x and y directions (the coupling integrals) as a function of the uniaxial anisotropy constant (K σ ) and the distance. We find that the IPUA increases the interaction between the disks allowing shorter energy transfer times. For our range of K σ values we get a drop in the values of τ of up to about 70%. From the lagrangian of the system we obtained the equations of motion and the coupling frequencies of the dynamic system as a function of distance and K σ . The coupling frequencies were also obtained from micromagnetic simulations. Our results of the simulations are in agreement with the analytical results.

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Section: Introductionmentioning

confidence: 99%

Controlling energy transfer time between two coupled magnetic vortex-state disks

Vigo-Cotrina

Guimarães

2016

Journal of Applied Physics

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“…Many magnetic nanoobjects have as ground state a magnetic vortex configuration, i.e., a pattern of magnetization tangential to concentric circles with a singularity at the center, where the magnetization points out of plane, the vortex core. [1][2][3] When a core is excited, i.e., displaced from its equilibrium, it performs a spiral-like motion back to the original position, with a well defined eigenfrequency of several hundred MHz. 4 Because of these dynamic properties, the vortices have many potential applications.…”

Section: Introductionmentioning

confidence: 99%

Magnetic vortex echoes

García

Sinnecker

Novais

et al. 2012

Journal of Applied Physics

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The dynamic properties of magnetic vortices have many potential applications in fast magnetic devices. Here we present a micromagnetic study of the motion of magnetic vortices in arrays of 100 nanodisks that have a normal distribution of diameters, as expected in real array systems, e.g., produced by nanolithography. The micromagnetic simulated experiments follow a protocol with an initial preparation and magnetic pulses that enable the control of the magnetic vortices initial positions and circular motion direction. The results show a new effect-the magnetic vortex echo (MVE) that arises from the refocusing of the overall array magnetization. We show, by using arrays with different interdisk separations, that MVE affords a means of characterizing them as regards the homogeneity and intensity of the interaction between its elements, properties that are relevant for device applications. We also show that a simple analytical model, analogous to the one that describes the spin echo in magnetic resonance, can be used to explain most features of the simulated magnetic vortex echo. V

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“…INTRODUCTION Soft ferromagnetic dots with sub-micrometer size can exhibit in the ground state a curling spin configuration known as magnetic vortex. 1,2 In this configuration, the spins form closed circuits in the plane of the dot while near the dot center, the spins of a small region (the vortex core) align perpendicularly to the plane in order to reduce exchange energy density. A magnetic vortex has two independent properties: circulation and polarity.…”

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confidence: 99%