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We investigate vortex configuration in antiferromagnetic thin discs. It is shown that the vortex acquires oscillatory dynamics with well-defined amplitude and frequency which may be controlled on demand by an alternating spin polarized…

Mesoscale and Nanoscale Physics · Physics 2018-12-19 R. L. Silva , R. C. Silva , R. J. C. Lopes , W. A. Moura-Melo , A. R. Pereira

Dynamics of vortices reflects the electronic states of quasiparticles in the core. To understand this, we investigated the following three issues. (1) We investigated the complex surface impedance, Zs, of YBa2Cu3Oy as a function of magnetic…

Controlling the magnetic ground states at the nanoscale is a long-standing basic research problem and an important issue in magnetic storage technologies. Here, we designed a nanostructured material that exhibits very unusual hysteresis…

Controlling domain wall motion is important due to the impact on the viability of proposed nanowire devices. One hurdle is slow domain wall speed when driven by fields greater than the Walker field, due to nucleation of vortices in the…

Materials Science · Physics 2009-11-13 Andrew Kunz , Sarah C. Reiff

The motion of a vortex domain wall in a ferromagnetic strip of submicron width under the influence of an external magnetic field exhibits three distinct dynamical regimes. In a viscous regime at low fields the wall moves rigidly with a…

Materials Science · Physics 2008-10-16 D. J. Clarke , O. A. Tretiakov , G. -W. Chern , Ya. B. Bazaliy , O. Tchernyshyov

We report a new reversal mechanism of magnetic vortex cores in nanodot elements driven by out-of-plane currents, occurring through two coupled edge-solitons via dynamic transformations between magnetic solitons of different topological…

Materials Science · Physics 2011-08-12 Ki-Suk Lee , Myoung-Woo Yoo , Youn-Seok Choi , Sang-Koog Kim

We propose the use of the gyrotropic motion of vortex cores in nanomagnets to produce a magnetic echo, analogous to the spin echo in NMR. This echo occurs when an array of nanomagnets, e.g., nanodisks, is magnetized with an in-plane (xy)…

Mesoscale and Nanoscale Physics · Physics 2012-01-18 F. Garcia , J. P. Sinnecker , E. R. P. Novais , A. P. Guimarães

The anharmonicity of the potential well confining the position of the magnetic vortex core is measured dynamically with a Magnetic Resonance Force Microscope (MRFM). The stray field of the MRFM tip is used to displace the core position away…

Mesoscale and Nanoscale Physics · Physics 2015-06-16 O. V. Sukhostavets , B. Pigeau , G. de Loubens , V. V. Naletov , O. Klein , K. Mitsuzuka , S. Andrieu , F. Montaigne , K. Y. Guslienko

Using micromagnetic simulations we demonstrate core reversal of a fixed magnetic skyrmion by modulating the perpendicular magnetic anisotropy of a nanomagnet with an electric field. We can switch reversibly between two skyrmion states and…

Mesoscale and Nanoscale Physics · Physics 2016-12-30 Dhritiman Bhattacharya , Md Mamun Al-Rashid , Jayasimha Atulasimha

The current-induced resonant excitation of a magnetic vortex core is investigated by means of analytical and micromagnetic calculations. We find that the radius and the phase shift of the resonant motion are not correctly described by the…

Other Condensed Matter · Physics 2009-11-13 Jung-Hwan Moon , Dong-Hyun Kim , Myung Hwa Jung , Kyung-Jin Lee

A model for a spin-torque nano-oscillator based on the self-sustained oscillation of a magnetic skyrmion is presented. The system involves a circular nanopillar geometry comprising an ultrathin film free magnetic layer with a strong…

Mesoscale and Nanoscale Physics · Physics 2016-08-03 F. Garcia-Sanchez , J. Sampaio , N. Reyren , V. Cros , J. -V. Kim

Spin-polarised radio-frequency currents, whose frequency is equal to that of the gyrotropic mode, will cause an excitation of the core of a magnetic vortex confined in a magnetic tunnel junction. When the excitation radius of the vortex…

Mesoscale and Nanoscale Physics · Physics 2016-05-04 A. S. Jenkins , R. Lebrun , E. Grimaldi , S. Tsunegi , P. Bortolotti , H. Kubota , K. Yakushiji , A. Fukushima , G. de Loubens , O. Klein , S. Yuasa , V. Cros

Topological magnetic textures are of great interest in various scientific and technological fields. To allow for precise control of nanoscale magnetism, it is of great importance to understand the role of intrinsic defects in the host…

Mesoscale and Nanoscale Physics · Physics 2021-07-22 Marcel Möller , John H. Gaida , Claus Ropers

We have investigated azimuthal spin-wave modes in magnetic vortex structures using time-resolved Kerr microscopy. Spatially resolved phase and amplitude spectra of ferromagnetic disks with diameters from 5 $\mu$m down to 500 nm reveal that…

Materials Science · Physics 2009-11-11 J. P. Park , P. A. Crowell

We consider the radial migration of vortices in two-dimensional isothermal gaseous disks. We find that a vortex core, orbiting at the local gas velocity, induces velocity perturbations that propagate away from the vortex as density waves.…

Earth and Planetary Astrophysics · Physics 2015-05-20 S. -J. Paardekooper , G. Lesur , J. C. B. Papaloizou

A nonlinear model of spin-wave excitation involving a point contact in a thin ferromagnetic film that includes the Oersted magnetic field contribution is presented. We consider the case of an external dc field applied perpendicular to the…

Other Condensed Matter · Physics 2007-05-23 M. A. Hoefer , T. J. Silva

Time-resolved soft X-ray transmission microscopy is applied to image the current-induced resonant dynamics of the magnetic vortex core realized in a micronsized Permalloy disk. The high spatial resolution better than 25 nm enables us to…

Two effects of oscillatory transformations of vortex textures in flat nanomagnets due to the application of an external field or a spin-polarized electric current are analytically described with relevance to soft-magnetic structures of…

Mesoscale and Nanoscale Physics · Physics 2012-06-06 Andrzej Janutka

Quantization effects of the nonlinear magnon-vortex interaction in ferromagnetic nanodisks are studied. We show that the circular geometry twists the spin-wave fields with spiral phase dislocations carrying quantized orbital angular…

Mesoscale and Nanoscale Physics · Physics 2022-09-14 Zhenyu Wang , H. Y. Yuan , Yunshan Cao , Peng Yan

Within the framework of the Landau-Lifshitz-Gilbert equation, using permalloy parameters, we study the statics and dynamics of flat circular magnetic nano-structures with an in-plane magnetic vortex configuration, putting particular…

Materials Science · Physics 2009-11-07 R. Höllinger , A. Killinger , U. Krey