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We experimentally demonstrate low-power-consumption vortex-core switching in magnetic nanodisks using tailored rotating magnetic fields that are produced with orthogonal and unipolar Gaussian-pulse currents. Optimal width of the orthogonal…

We report direct imaging by means of x-ray photoemission electron microscopy of the dynamics of magnetic vortices confined in micron-size circular Permalloy dots that are 30 nm thick. The vortex core positions oscillate on a 10-ns timescale…

Mesoscale and Nanoscale Physics · Physics 2009-11-11 K. Yu. Guslienko , X. F. Han , D. J. Keavney , R. Divan , S. D. Bader

Vortex core polarity switching in NiFe disks has been evidenced using an all-electrical rectification scheme. Both simulation and experiments yield a consistent loss of the rectified signal when driving the core at high powers near its…

Spin textures that are not readily available in the domain structures of continuous magnetic thin films can be stabilized when patterned to micro/nano scales due to the dominant effect of dipolar magnetic interactions. Fabrication of such…

Competition with magnetism is at the heart of high temperature superconductivity, most intensely felt near a vortex core. To investigate vortex magnetism we have developed a spatially resolved probe using nuclear magnetic resonance. Our…

Superconductivity · Physics 2010-11-09 A. M. Mounce , S. Oh , S. Mukhopadhyay , W. P. Halperin , A. P. Reyes , P. L. Kuhns , K. Fujita , M. Ishikado , S. Uchida

Because of its stability, the polarity of a magnetic vortex core (VC) is a candidate for binary data storage. Switching can be accomplished, e.g, by driving the VC above a critical velocity $v_c$. Here, we report on controlled and repeated…

Mesoscale and Nanoscale Physics · Physics 2020-07-13 Mahdi Mehrnia , Jeremy Trimble , Olle Heinonen , Jesse Berezovsky

We present a frequency-domain study of the dynamic behavior of a magnetic vortex core within a single Permalloy disk by means of electrical detection and micromagnetic simulations. When exciting the vortex core dynamics in a non-linear…

Mesoscale and Nanoscale Physics · Physics 2022-12-19 Lakshmi Ramasubramanian , Vadym Iurchuk , Serhii Sorokin , Olav Hellwig , Alina Maria Deac

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

We investigated the spin dynamics of a vortex state in a core-shell magnetic nanodisk driven by an oscillating field applied perpendicular to the disk plane by means of micromagnetic simulations. The nanodisk comprises a Py (Fe0.2Ni0.8)…

Mesoscale and Nanoscale Physics · Physics 2018-08-01 Huirong Zhao , Ruifang Wang

The bistability of the core magnetization of nano-scaled magnets with a magnetic vortex configuration has great potential for data storage applications. To exploit this, reliable switching between the two possible states is needed. Time…

The switching of a vortex core of a single disk in an array of a multilayer system is investigated by micromagnetic simulation. We found that the perpendicular uniaxial anisotropy (PUA) decreases the frequencies of the azimuthal mode in…

Mesoscale and Nanoscale Physics · Physics 2018-05-09 H. Vigo-Cotrina , A. P. Guimarães

This study conducts a comprehensive investigation into the reversal mechanism of magnetic vortex cores in a nanopillar system composed of two coupled ferromagnetic dots under zero magnetic field conditions. The research employs a…

Materials Science · Physics 2023-02-24 A. Hamadeh , A. Koujok , S. Perna , D. R. Rodrigues , A. Riveros , V. Lomakin , G. Finocchio , G. de Loubens , O. Klein , P. Pirro

It is well known that azimuthal spin wave modes of magnetic vortex state in permalloy nanodisks have circular symmetry. Intuitively, magnetic materials having magnetocrystalline anisotropy is not compatible with the circular symmetry of the…

Mesoscale and Nanoscale Physics · Physics 2020-01-08 Huirong Zhao , Zhengyun Lei , Ruifang Wang

We perform a comparative study of spin transfer induced excitation of the gyrotropic motion of a vortex core with either uniform or vortex spin polarizers. The microwave output voltage associated with the vortex dynamics, detected in both…

In a nanopillar with dipolarly coupled vortices, we present an experimental and simulation study to understand how the interplay between the bias field and spin transfer torque impacts reversal of the vortex cores. We find that, depending…

Mesoscale and Nanoscale Physics · Physics 2015-06-12 N. Locatelli , A. E. Ekomasov , A. V. Khvalkovskiy , Sh. A. Azamatov , K. A. Zvezdin , J. Grollier , E. G. Ekomasov , V. Cros

Spin-polarized radio frequency (RF) currents and RF-Oersted fields resonantly excite a magnetic vortex core confined in a micron-scale soft magnetic disk. In this study, we measured the rectifying voltage spectra caused by the anisotropic…

We present an experimental investigation of radial spin-wave modes in magnetic nano-disks with a vortex ground state. The spin-wave amplitude was measured using a frequency-resolved magneto optical network analyzer, allowing for…

Mesoscale and Nanoscale Physics · Physics 2015-06-23 M. Helsen , A. Gangwar , J. De Clercq , A. Vansteenkiste , B. Van Waeyenberge

A magnetic vortex core in a ferromagnetic circular nanodot has a resonance frequency originating from the confinement of the vortex core. By the micromagnetic simulation including the spin-transfer torque, we show that the vortex core can…

Other Condensed Matter · Physics 2009-11-11 Shinya Kasai , Yoshinobu Nakatani , Kensuke Kobayashi , Hiroshi Kohno , Teruo Ono

In the emerging field of magnonics, spin waves are foreseen as signal carriers for future spintronic information processing and communication devices, owing to both the very low power losses and a high device miniaturisation potential…

We observe the dynamics of a single magnetic vortex in the presence of a random array of pinning sites. At low excitation amplitudes, the vortex core gyrates about its equilibrium position with a frequency that is characteristic of a single…

Materials Science · Physics 2009-11-11 R. L. Compton , P. A. Crowell