Coupled perturbed heteroclinic cycles: Synchronization and dynamical behaviors of spin-torque oscillators

Li, Dong; Zhou, Yan; Hu, Bambi; Zhou, Changsong

doi:10.1103/physrevb.84.104414

Cited by 22 publications

(21 citation statements)

References 68 publications

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“…For this reason the study of its dynamical behavior, leading to the decisive improvement of a general understanding of non-linear effects in magnetic systems, is one of the most important research tasks in non-linear magnetic phenomena. Especially various synchronization regimes in ensembles of these oscillators represent a very challenging fundamental problem, which solution for various cases has been the subject of many recent publications [3][4][5][6][7].…”

Section: Introductionmentioning

confidence: 99%

Robust synchronization of an arbitrary number of spin-torque-driven vortex nano-oscillators

Erokhin¹,

Berkov²

2014

Phys. Rev. B

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Non-linear magnetization dynamics in ferromagnetic nanoelements excited by the spin-polarized dc-current is one of the most intensively studied phenomena in solid state magnetism. Despite immense efforts, synchronization of oscillations induced in several such nanoelements (spin-torque driven nanooscillators, or STNO) still represents a major challenge both from the fundamental and technological points of view. In this paper we propose a system where synchronization of any number of STNOs, represented by magnetization vortices inside squared nanoelements, can be easily achieved. Using full-scale micromagnetic simulations we show that synchronization of these STNOs is extremely dynamically stable due to their very large coupling energy provided by the magnetodipolar interaction. Finally, we demonstrate that our concept allows robust synchronization of an arbitrary number of STNOs (arranged either as a 1D chain or as a 2D array), even when current supplying nanocontacts have a broad size distribution.

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Section: Introductionmentioning

confidence: 99%

Robust synchronization of an arbitrary number of spin-torque-driven vortex nano-oscillators

Erokhin¹,

Berkov²

2014

Phys. Rev. B

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“…Indeed, as self-sustained oscillators like electronic generators and lasers, they must demonstrate typical for this class of physical systems effects of phase locking by external injection, and of mutual synchronization if two or more devices are coupled 6 . Beside from the fundamental interest, synchronization of STOs is also of high practical relevance, as a way to increase the output power of otherwise rather weak individual STOs 7 .In the context of uniform STOs, the mostly promising way of coupling the STOs to achieve synchrony is to connect them in serial electrically via the common microwave current [8][9][10][11][12] (in experiments 13,14 a synchronization of two STOs was observed; however the coupling was not the electrical one, but due to spin waves, as the distance between two STOs build on the same mesa was about 500 nm). In Ref.…”

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confidence: 99%

Robust synchronization of spin-torque oscillators with anLCRload

Pikovsky

2013

Phys. Rev. E

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We study dynamics of a serial array of spin-torque oscillators with a parallel inductor-capacitor-resistor (LCR) load. In a large range of parameters the fully synchronous regime, where all the oscillators have the same state and the output field is maximal, is shown to be stable. However, not always such a robust complete synchronization develops from a random initial state; in many cases nontrivial clustering is observed, with a partial synchronization resulting in a quasiperiodic or chaotic mean-field dynamics.

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“…Instead, numerical simulations must be performed in order to completely reveal all the eigenstates of the system. [18][19][20] This also facilitates our understanding of the coexisting regions, such as L/N and S/N, which appear in the analytical phase diagram. These bistable regions correspond to hysteretic switching between different static states and between static and dynamic states.…”

Section: Eigenvalue Analysis and The Macrospin Modelmentioning

confidence: 92%

“…To solve the power limitation problem, two solutions have been proposed, namely, (a) improving the magnetoresistance (MR) of a single device by optimizing the material properties and device fabrication, 13,14 and (b) synchronizing a series of STNOs to produce enhanced phase-coherent microwave oscillation. 5,[15][16][17][18][19][20][21] Additionally, various efforts have been made to remove the applied magnetic field, which typically ranges from a few hundred Oersteds to over 1 T. The most widely adopted zero-field operation approaches include STNOs with a perpendicularly magnetized fixed 22 or free layer, 23,24 vortex oscillators, [25][26][27][28][29][30] wavy-torque spin-torque oscillators, 31 and tilted-polarizer STNOs (TP-STNOs). [32][33][34][35][36][37] A TP-STNO is a nanosized spintronic device, where the magnetization of the fixed layer is tilted with respect to the film plane.…”

Section: Introductionmentioning

confidence: 99%

Macrospin and micromagnetic studies of tilted polarizer spin-torque nano-oscillators

Zhou

Hong

Liu

et al. 2012

Journal of Applied Physics

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Experimental study of a compact P-band coaxial relativistic backward wave oscillator with three periods slow wave structure Phys. Plasmas 19, 083113 (2012) Ultra-broadband infrared pump-probe spectroscopy using synchrotron radiation and a tuneable pump Rev. Sci. Instrum. 82, 063101 (2011) Plasma expansion and impedance collapse in a foil-less diode for a klystronlike relativistic backward wave oscillator Phys. Plasmas 17, 123107 (2010) Terahertz generation and chaotic dynamics in single-walled zigzag carbon nanotubes Chaos 19, 033136 (2009) Measurement of intense coherent synchrotron radiation at frequencies around 0.1 THz using the compact Sband linacUsing nonlinear dynamical systems theory, we analytically studied a spin-torque device in which the magnetization of the polarizer (the fixed layer) is tilted at an arbitrary angle out of the thin-film plane. While the analytical theory can determine the major features of the system, macrospin simulations were employed to demonstrate the unique characteristics of the system, such as the hysteretic switching between bistable states. Material dependencies of the dynamic and static state diagrams were also studied in the framework of the macrospin model. Full-scale micromagnetics simulations were finally performed to reveal more subtle features of the dynamics of such tilted polarizer systems. Both the macrospin and micromagnetics simulations gave quantitatively the same results as our analytical theory. V C 2012 American Institute of Physics. [http://dx.

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Coupled perturbed heteroclinic cycles: Synchronization and dynamical behaviors of spin-torque oscillators

Cited by 22 publications

References 68 publications

Robust synchronization of an arbitrary number of spin-torque-driven vortex nano-oscillators

Robust synchronization of an arbitrary number of spin-torque-driven vortex nano-oscillators

Robust synchronization of spin-torque oscillators with anLCRload

Macrospin and micromagnetic studies of tilted polarizer spin-torque nano-oscillators

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