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Related papers: Spin-torque driven magnetic vortex self-oscillatio…

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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

Classical and quantum theory of spin waves in the vortex state of a mesoscopic sub-micron magnetic disk has been developed with account of the finite mass density of the vortex. Oscillations of the vortex core resemble oscillations of a…

Mesoscale and Nanoscale Physics · Physics 2015-06-11 Ricardo Zarzuela , Eugene Chudnovsky , Javier Tejada

Scanning transmission x-ray microscopy is employed to investigate experimentally the reversal of the magnetic vortex core polarity in cylindrical Ni81Fe19 nanodisks triggered by two orthogonal monopolar magnetic field pulses with peak…

Type-II superconductors exhibit hysteretic behavior due to the presence of quantum vortices, and the order in which temperature and external field are varied plays a decisive role. Here we take current, rather than magnetic field, as the…

In a vortex-state magnetic nano-disk, the static magnetization is curling in the plane, except in the core region where it is pointing out-of-plane, either up or down leading to two possible stable states of opposite core polarity p.…

We study theoretically the detection and possible utilization of electric current-induced mechanical torques in ferromagnetic-normal metal heterostructures that are generated by spin-flip scattering or the absorption of transverse spin…

Mesoscale and Nanoscale Physics · Physics 2010-01-01 Alexey A. Kovalev , Gerrit E. W. Bauer , Arne Brataas

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

Upon passing an a.c. electrical current along magnetic micro- or nanostrips, the measurement of a d.c. voltage that depends sensitively on current frequency and applied field has been recently reported by A. Yamaguchi and coworkers. It was…

Other Condensed Matter · Physics 2009-11-13 Andre Thiaville , Yoshinobu Nakatani

In the present study, we investigate a dynamical mode beyond the gyrotropic (G) motion of a magnetic vortex core in a confined magnetic disk of a nano-pillar spin torque nano oscillator. It is characterized by the in-plane circular…

A vortex-antivortex dipole can be generated due to current with in-plane spin-polarization, flowing into a magnetic element, which then behaves as a spin transfer oscillator. Its dynamics is analyzed using the Landau-Lifshitz equation…

Mesoscale and Nanoscale Physics · Physics 2015-06-17 Stavros Komineas

The spin dynamics are calculated for a model system consisting of magnetically soft, layered nanomagnets, in which two ferromagnetic (F) cylindrical dots, each with a magnetic vortex ground state, are separated by a non-magnetic spacer (N).…

Mesoscale and Nanoscale Physics · Physics 2009-11-11 K. Yu. Guslienko , K. S. Buchanan , S. D. Bader , V. Novosad

We present a simple and fast method to simulate spin-torque driven magnetisation dynamics in nano-pillar spin-valve structures. The approach is based on the coupling between a spin transport code based on random matrix theory and a…

Mesoscale and Nanoscale Physics · Physics 2017-09-27 Simone Borlenghi , M. R. Mahani , Hans Fangohr , Matteo Franchin , Anna Delin , Jonas Fransson

Control over quantum systems is typically achieved by time-dependent electric or magnetic fields. Alternatively, electronic spins can be controlled by spin-polarized currents. Here we demonstrate coherent driving of a single spin by a…

Mesoscale and Nanoscale Physics · Physics 2024-06-26 Stepan Kovarik , Richard Schlitz , Aishwarya Vishwakarma , Dominic Ruckert , Pietro Gambardella , Sebastian Stepanow

A new research topic in spintronics relating to the operation principles of brain-inspired computing is input-driven magnetization dynamics in nanomagnet. In this paper, the magnetization dynamics in a vortex spin-torque oscillator (STO)…

Mesoscale and Nanoscale Physics · Physics 2023-06-26 Yusuke Imai , Kohei Nakajima , Sumito Tsunegi , Tomohiro Taniguchi

In a nanomagnet (whose total spin S< 1000), very small polarized currents can lead to magnetic reversal. Treating on the same footing the transport and magnetic properties of a nanomagnet connected to magnetic leads via tunneling barriers,…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 X. Waintal , O. Parcollet

Equilibrium magnetization distribution of the vortex state magnetic nanoparticle is affected by the influence of the spin-transfer torque: an off-center out--of--plane vortex appears in the case of the disk shape particle and pure planar…

Mesoscale and Nanoscale Physics · Physics 2015-05-20 Volodymyr P. Kravchuk , Denis D. Sheka , Franz G. Mertens , Yuri Gaididei

We have studied magnetic vortex oscillations in soft sub-micron cylindrical dots with variable thickness and diameter by an analytical approach and micromagnetic simulations. We have considered two kinds of modes of the vortex magnetization…

Materials Science · Physics 2009-11-10 K. Yu. Guslienko , W. Scholz , R. W. Chantrell , V. Novosad

We discuss a possible mechanism of the spin-transfer induced oscillations of a vortex in the free layer of spin-valve nanostructures, in which the polarizer layer has a planar magnetization. We demonstrate that if such planar polarizer is…

Materials Science · Physics 2015-05-18 A. V. Khvalkovskiy , J. Grollier , N. Locatelli , Ya. V. Gorbunov , K. A. Zvezdin , V. Cros

We reverse the magnetic vortex curling direction of ferromagnetic nanodisk by applying a circular Oersted field. The nanodisk is fabricated without breaking its symmetry. The Oersted field is induced by passing current through an atomic…

Mesoscale and Nanoscale Physics · Physics 2014-12-01 Wen-Ming Ju , Mark Tuominen , Nihar Pradhan , Jessica Bickel , Kathy Aidala

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