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We study a nonlinear spin dynamics of a ferromagnetic ring in a vortex state induced by the spin-polarized current. We also suggest to use the ferromagnetic ring as a free layer of a coreless vortex spin-transfer nano-oscillator. The…

Mesoscale and Nanoscale Physics · Physics 2023-12-08 Vera Uzunova , Boris A. Ivanov

We experimentally demonstrate that large magnetic vortex oscillations can be parametrically excited in a magnetic tunnel junction by the injection of radio-frequency (rf) currents at twice the natural frequency of the gyrotropic vortex core…

Mesoscale and Nanoscale Physics · Physics 2015-06-15 P. Bortolotti , C. Serpico , E. Grimaldi , A. Dussaux , J. Grollier , V. Cros , K. Yakushiji , A. Fukushima , H. Kubota , R. Matsumoto , S. Yuasa

Time-resolved X-ray microscopy is used to image the influence of alternating high-density currents on the magnetization dynamics of ferromagnetic vortices. Spin-torque induced vortex gyration is observed in micrometer-sized permalloy…

Finding new energy-efficient methods for exciting magnetization dynamics is one of the key challenges in magnonics. In this work, we present an approach to excite the gyrotropic dynamics of magnetic vortices through the phenomenon of…

Applied Physics · Physics 2023-09-12 A. Koujok , A. Riveros , D. R. Rodrigues , G. Finocchio , M. Weiler , A. Hamadeh , P. Pirro

In this letter we address the vortex core dynamics involved in gyration excitation and damping change by out-of-plane oscillating magnetic fields. When the vortex core is at rest under the effect of in-plane bias magnetic fields, the spin…

Mesoscale and Nanoscale Physics · Physics 2014-10-14 Liu Yan , Li Huanan , Hu Yong , Du An

A new current induced spin-torque transfer effect has been observed in a single ferromagnetic layer without resorting to multilayers. At a specific current density of one polarity injected from a point contact, abrupt resistance changes due…

Condensed Matter · Physics 2009-11-07 Y. Ji , C. L. Chien

Excitation of spin wave modes of a vortex-state magnetic dot by an out-of-plane oscillating magnetic field is studied numerically in the presence of a static in-plane magnetic field. It is shown, that the application of the in-plane static…

Mesoscale and Nanoscale Physics · Physics 2016-04-26 Yan Liu , Yan Zhou , P. Dürrenfeld , Y. Yin , D. W. Wang , A. N. Slavin , A. Ruotolo

We report the rectification of a constant wave radio frequency (RF) current by using a single-layer magnetic nanowire; a direct-current voltage is resonantly generated when the RF current flows through the nanowire. The mechanism of the…

Materials Science · Physics 2009-11-11 A. Yamaguchi , H. Miyajima , T. Ono , Y. Suzuki , S. Yuasa , A. Tulapurkar , Y. Nakatani

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…

Vortex pairs in magnetic nanopillars with strongly coupled cores and pinning of one of the cores by a morphological defect, are used to perform resonant pinning spectroscopy, in which a microwave excitation applied to the nanopillar…

Mesoscale and Nanoscale Physics · Physics 2018-03-14 E. Holmgren , A. Bondarenko , B. A. Ivanov , V. Korenivski

A spin-polarized current with the polarization perpendicular to the plane of a vortex-state disk results in renormalization of the effective damping for a given magnetization mode, and the effective damping becomes zero if the current…

Materials Science · Physics 2009-11-13 B. A. Ivanov , C. E. Zaspel

Effects of fermionic zero modes (bound states in a vortex core) on the rotational dynamics of vortices with sponaneously broken axisymmetry are considered. The results are compared with the Helsinki experiments where the vortex cores were…

Superconductivity · Physics 2009-10-30 N. B. Kopnin , G. E. Volovik

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

The magnetic vortex structure, an important ground state configuration in micron and sub-micron sized ferromagnetic thin film platelets, is characterized by a curling in-plane magnetization and, in the center, a minuscule region with…

Transfer of angular momentum from a spin-polarized current to a ferromagnet provides an efficient means to control the dynamics of nanomagnets. A peculiar consequence of this spin-torque, the ability to induce persistent oscillations of a…

Other Condensed Matter · Physics 2015-06-25 V. S. Pribiag , I. N. Krivorotov , G. D. Fuchs , P. M. Braganca , O. Ozatay , J. C. Sankey , D. C. Ralph , R. A. Buhrman

We calculated the main dynamic parameters of the spin polarized current induced magnetic vortex oscillations in nanopillars, such as the range of current density, where a vortex steady oscillations exist, the oscillation frequency and orbit…

Other Condensed Matter · Physics 2009-12-31 Konstantin Y. Guslienko , Gloria R. Aranda , Julian M. Gonzalez

Antivortices in ferromagnetic thin-film elements are in-plane magnetization configurations with a core pointing perpendicular to the plane. By using micromagnetic simulations, we find that magnetic antivortices gyrate on elliptical orbits…

Other Condensed Matter · Physics 2009-11-13 Andre Drews , Benjamin Krueger , Markus Bolte , Guido Meier

Frequency multiplication involves generating harmonics from an input frequency, a technique particularly useful for integrating spin-wave devices operating at different frequencies. While topological magnetic textures offer distinct…

Mesoscale and Nanoscale Physics · Physics 2024-12-19 Cheng-Jie Wang , Yuxin Li , Zhe Ding , Pengfei Wang , Fazhan Shi , Jiangfeng Du

Recent radio frequency scanning tunneling spectroscopy (rf-STS) experiments have demonstrated nuclear and electron spin excitations up to $\pm12\hbar$ in a single molecular spin quantum dot (qudot). Despite the profound experimental…

Performance of magnetoresistive sensors is today mainly limited by their 1/f low-frequency noise. Here, we study this noise component in vortex-based TMR sensors. We compare the noise level in different magnetization configurations of the…