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The vortex state, characterized by an in-plane closed flux domain structure and an out-of-plane magnetization at its centre (the vortex core), is one of the magnetic equilibria of thin soft ferromagnetic micron-size dots. In the last two…

Mesoscale and Nanoscale Physics · Physics 2015-06-03 Ricardo Zarzuela , Saül Vélez , Joan Manel Hernandez , Javier Tejada , Valentyn Novosad

A controlled local enhancement of superconductivity yields unexpected modifications in the vortex dynamics. This local enhancement has been achieved by designing an array of superconducting Nb nanostructures embedded in a V superconducting…

The influence of a small perturbation on a cavity mode plays an important role in fields like optical sensing, cavity quantum electrodynamics and cavity optomechanics. Typically, the resulting cavity frequency shift directly relates to the…

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

Studies involving vortex dynamics and their interaction with pinning centers are an important ingredient to reach higher critical currents in superconducting materials. The vortex distribution around arrays of engineered defects, such as…

The energy of a displaced magnetic vortex in a cylindrical particle made of isotropic ferromagnetic material (magnetic dot) is calculated taking into account the magnetic dipolar and the exchange interactions. Under the simplifying…

Mesoscale and Nanoscale Physics · Physics 2009-10-31 Konstantin Yu. Guslienko , Konstantin L. Metlov

To verify the exact underlying mechanism of ultrafast vortex-core reversal as well as the vortex state stability we conducted numerical calculations of the dynamic evolution of magnetic vortices in Permalloy cylindrical nanodots under an…

Materials Science · Physics 2007-11-20 Ki-Suk Lee , Konstantin Y. Guslienko , Jun-Young Lee , Sang-Koog Kim

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…

We study the stability and structure of vortices emerging in two-dimensional quantum dots in high magnetic fields. Our results obtained with exact diagonalization and density-functional calculations show that vortex structures can be found…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 H. Saarikoski , S. M. Reimann , E. Rasanen , A. Harju , M. Puska

Micron-sized magnetic platelets in the flux closed vortex state are characterized by an in-plane curling magnetization and a nanometer-sized perpendicularly magnetized vortex core. Having the simplest non-trivial configuration, these…

Magnetic platelets with a vortex configuration are attracting considerable attention. The discovery that excitation with small in-plane magnetic fields or spin polarised currents can switch the polarisation of the vortex core did not only…

Vortex dynamics in superfluids is investigated in the framework of the nonlinear Schr\"{o}dinger equation. The natural motion of the vortex is of cyclotron type, whose frequency is found to be on the order of phonon velocity divided by the…

Condensed Matter · Physics 2009-10-28 E. Demircan , P. Ao , Q. Niu

Under the action of an alternating perpendicular magnetic field the polarity of the vortex state nanodisk can be efficiently switched. We predict the regular and chaotic dynamics of the vortex polarity and propose simple analytical…

Mesoscale and Nanoscale Physics · Physics 2013-08-09 Oleksandr V. Pylypovskyi , Denis D. Sheka , Volodymyr P. Kravchuk , Franz G. Mertens , Yuri Gaididei

We demonstrate that there is a long-range vortex-vortex attraction in ferromagnetic superconductors due to polarization of the magnetic moments. Vortex clusters are then stabilized in the ground state for low vortex densities. The motion of…

Superconductivity · Physics 2012-11-29 Shi-Zeng Lin , Lev N. Bulaevskii , Cristian D. Batista

Controlling the vortex chirality in ferromagnetic nanodots and nanorings has been a topic of investigation for the last few years. Many control methods have been proposed and it has been found that the control is related to the breaking of…

Mesoscale and Nanoscale Physics · Physics 2024-04-22 Uladzislau Makartsou , Mathieu Moalic , Mateusz Zelent , Michal Mruczkiewicz , Maciej Krawczyk

We report experimental and analytical work on spin-transfer torque induced vortex dynamics in metallic nanopillars with in-plane magnetized layers. We study nanopillars with a diameter of 150 nm, containing two Fe layers with a thickness of…

Mesoscale and Nanoscale Physics · Physics 2011-09-14 Volker Sluka , Attila Kakay , Alina M. Deac , Daniel E. Bürgler , Riccardo Hertel , Claus M. Schneider

We have performed micromagnetic simulations of the vortex gyrotropic mode resonance in a range of disk geometries subject to spatially uniform out-of-plane magnetic fields. For disks of small lateral dimensions, we observe a drop-off in the…

Mesoscale and Nanoscale Physics · Physics 2016-12-14 Jasper P. Fried , Hans Fangohr , Mikhail Kostylev , Peter J. Metaxas

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

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

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