Magnetic Vortex Core Dynamics in Cylindrical Ferromagnetic Dots

Guslienko, K. Yu.; Han, Xiufeng; Keavney, D. J.; Divan, Ralu; Bader, S. D.

doi:10.1103/physrevlett.96.067205

Cited by 241 publications

(180 citation statements)

References 26 publications

Supporting

Mentioning

167

Contrasting

Unclassified

Order By: Relevance

“…9 The existence of such critical velocity (u c =250 m/s for permalloy dots) was recently confirmed by time-resolved magnetic scanning transmission x-ray microscopy 46 for vortex core reversal in FeNi dots. We used in Figs.…”

Section: Nonlinear Effects and Vortex-core Reversalmentioning

confidence: 92%

See 1 more Smart Citation

Nonlinear gyrotropic vortex dynamics in ferromagnetic dots

2010

View full text Add to dashboard Cite

The quasistationary and transient (nanosecond) regimes of nonlinear vortex dynamics in a soft magnetic dot driven by an oscillating external field are studied. We derive a nonlinear dynamical system of equations for the vortex core position and phase, assuming that the main source of nonlinearity comes from the magnetostatic energy. In the stationary regime, we demónstrate the occurrence of a fold-over bifurcation and calcúlate analytically the resonant nonlinear vortex frequencies as a function of the amplitude and frequency of the applied driving field. In the transient regime, we show that the vortex core dynamics are described by an oscillating trajectory radius. The resulting dynamics contain múltiple frequencies with amplitude decaying in time. Finally, we evalúate the ranges of the system parameters leading to a vortex core instability (core polarization re versal).

show abstract

Section: Nonlinear Effects and Vortex-core Reversalmentioning

confidence: 92%

“…The nonlinear coefficients can also be calculated within the pole-free model, 9,17 and their signs are /?>0, <5>0. The linear response coefficient is £=2/(3/?)…”

Section: Notation If H(t)=h 0 E'"" Then H(t)=h(t)m S Vmentioning

confidence: 99%

Nonlinear gyrotropic vortex dynamics in ferromagnetic dots

2010

View full text Add to dashboard Cite

show abstract

“…This dynamic behavior has been explained as the movement of the vortex core in its self-induced magnetostatic restoring force. 3 The eigenfrequency of the gyration mode typically lies in the subgigahertz range and is dependent on the size of the structure. For disk-shaped structures, it has been theoretically and experimentally found that for given material parameters, the gyration frequency approximately scales with the geometrical aspect ratio, with only a slight dependence on the thickness and lateral size separately.…”

Section: Introductionmentioning

confidence: 99%

Influence of domain wall pinning on the dynamic behavior of magnetic vortex structures: Time-resolved scanning x-ray transmission microscopy in NiFe thin film structures

et al. 2008

View full text Add to dashboard Cite

Artificial domain wall pinning sites were created in micron-sized thin-film Ni 80 Fe 20 structures, and their influence on the vortex dynamics was investigated by using time-resolved scanning transmission x-ray microscopy. The domain wall pinning sites were introduced by means of focused ion beam etching in the form of antidots. The vortex gyration frequency increased in square-shaped structures but not in similarly modified disk-shaped structures, where no domain walls are present. This demonstrates that the domain wall pinning is causing the increased frequency. The effect is explained by the confinement of the domain wall motion to the portion of the structure that is circumscribed by the antidots and is in agreement with micromagnetic simulations.

show abstract

“…The vortex magnetization distribution stability as well as the vortex excitations were studied in Refs. [5][6][7][8][9][10][11][12][13][14][15].…”

Section: Introductionmentioning

confidence: 99%

Limits for the vortex state spin torque oscillator in magnetic nanopillars: Micromagnetic simulations for a thin free layer

Aranda

González

Val

et al. 2010

Journal of Applied Physics

View full text Add to dashboard Cite

Anomalous magnetic properties of 7nm single-crystal Co3O4 nanowires J. Appl. Phys. 111, 013910 (2012) High field-gradient dysprosium tips for magnetic resonance force microscopy Appl. Phys. Lett. 100, 013102 (2012) Dipolar interactions in magnetic nanowire aggregates J. Appl. Phys. 110, 123924 (2011) Dielectric and spin relaxation behaviour in DyFeO3 nanocrystals J. Appl. Phys. 110, 124301 (2011) Finite size versus surface effects on magnetic properties of antiferromagnetic particles Appl. Phys. Lett. 99, 232507 (2011) Additional information on J. Appl. Phys. We report micromagnetic simulations of magnetization dynamics of a vortex state in the free layer of a circular nanopillar excited by the spin transfer torque effect of a perpendicular to the layer ͑dot͒ plane spin-polarized electrical current. The magnetization of the reference layer ͑polarizer͒ is assumed to be fixed. A new regime of the dynamic magnetization response to the current is reported: vortex expelling from the dot, subsequent in-plane magnetization oscillations in single domain state, and the vortex return with an opposite core polarization. We analyze conditions ͑limits of the vortex state as a nano-oscillator͒ to achieve steady magnetization oscillations corresponding to a gyrotropic motion of the vortex core in terms of the current intensity. These conditions are formulated via the critical currents and vary greatly with the magnetic damping parameter and the cell size used for micromagnetic simulations. The existing experiments on the current induced magnetization dynamics in nanopillars and nanocontacts are discussed.

show abstract

Magnetic Vortex Core Dynamics in Cylindrical Ferromagnetic Dots

Cited by 241 publications

References 26 publications

Nonlinear gyrotropic vortex dynamics in ferromagnetic dots

Nonlinear gyrotropic vortex dynamics in ferromagnetic dots

Influence of domain wall pinning on the dynamic behavior of magnetic vortex structures: Time-resolved scanning x-ray transmission microscopy in NiFe thin film structures

Limits for the vortex state spin torque oscillator in magnetic nanopillars: Micromagnetic simulations for a thin free layer

Contact Info

Product

Resources

About