skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Viscous dynamics of vortices in a ferromagnetic film

; ;
Publication Date:
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
Grant/Contract Number:
Resource Type:
Journal Article: Publisher's Accepted Manuscript
Journal Name:
Physical Review B
Additional Journal Information:
Journal Volume: 97; Journal Issue: 5; Related Information: CHORUS Timestamp: 2018-02-22 10:13:22; Journal ID: ISSN 2469-9950
American Physical Society
Country of Publication:
United States

Citation Formats

Reitz, Derek, Ghosh, Anirban, and Tchernyshyov, Oleg. Viscous dynamics of vortices in a ferromagnetic film. United States: N. p., 2018. Web. doi:10.1103/PhysRevB.97.054424.
Reitz, Derek, Ghosh, Anirban, & Tchernyshyov, Oleg. Viscous dynamics of vortices in a ferromagnetic film. United States. doi:10.1103/PhysRevB.97.054424.
Reitz, Derek, Ghosh, Anirban, and Tchernyshyov, Oleg. 2018. "Viscous dynamics of vortices in a ferromagnetic film". United States. doi:10.1103/PhysRevB.97.054424.
title = {Viscous dynamics of vortices in a ferromagnetic film},
author = {Reitz, Derek and Ghosh, Anirban and Tchernyshyov, Oleg},
abstractNote = {},
doi = {10.1103/PhysRevB.97.054424},
journal = {Physical Review B},
number = 5,
volume = 97,
place = {United States},
year = 2018,
month = 2

Journal Article:
Free Publicly Available Full Text
This content will become publicly available on February 22, 2019
Publisher's Accepted Manuscript

Save / Share:
  • Perpendicular magnetic anisotropy (PMA) and low magnetic damping are the key factors for the free layer magnetization switching by spin transfer torque technique in magnetic tunnel junction devices. The magnetization precessional dynamics in soft ferromagnetic FeTaC thin film with a stripe domain structure was explored in broad band frequency range by employing micro-strip ferromagnetic resonance technique. The polar angle variation of resonance field and linewidth at different frequencies have been analyzed numerically using Landau-Lifshitz-Gilbert equation by taking into account the total free energy density of the film. The numerically estimated parameters Landé g-factor, PMA constant, and effective magnetization are foundmore » to be 2.1, 2 × 10{sup 5} erg/cm{sup 3} and 7145 Oe, respectively. The frequency dependence of Gilbert damping parameter (α) is evaluated by considering both intrinsic and extrinsic effects into the total linewidth analysis. The value of α is found to be 0.006 at 10 GHz and it increases monotonically with decreasing precessional frequency.« less
  • We have investigated a coupled motion of two vortex cores in ferromagnetic/nonmagnetic/ferromagnetic trilayer cynliders by means of micromagnetic simulation. Dynamic motion of two vortex with parallel and antiparallel relative chiralities of curling spins around the vortex cores have been examined after excitation by 1-ns pulsed external field. With systematic variation in non-magnetic spacer layer thickness from 0 to 20 nm, the coupling between two cores becomes significant as the spacer becomes thinner. Significant coupling leads to a nonlinear chaotic coupled motion of two vortex cores for the parallel chiralities and a faster coupled gyrotropic oscillation for the antiparallel chiralities.
  • Nonlinear dynamics of vortices in current-carrying long Josephson contacts is considered for the cases of weak ([lambda][sub [ital J]][much gt][lambda]) and strong ([lambda][sub [ital J]][much lt][lambda]) couplings, where [lambda][sub [ital J]] and [lambda] are the Josephson and London penetration depths, respectively. The first case concerns the Josephson vortices described by the sine-Gordon equation, whereas the case [lambda][sub [ital J]][much lt][lambda] corresponds to Abrikosov-like vortices with highly anisotropic Josephson cores which are described by an integral equation for the phase difference [ital cphi] within the framework of a nonlocal Josephson electrodynamics. At [lambda][sub [ital J]][much lt][lambda], an exact solution for themore » moving vortex in the overdamped regime is obtained, the fluxon velocity [ital v]([ital j]) and the voltage-current characteristic [ital V]([ital j]) are calculated. It is shown that the lack of the Lorentz invariance of the integral equation for [ital cphi] in the nonlocal regime leads to specific features of the vortex dynamics as compared to the Josephson vortices. The results obtained are employed for the description of nonlinear viscous motion of magnetic flux along planar crystalline defects in superconductors. It is shown that any percolating network of planar defects can considerably reduce the critical current, change the field dependence of the flux-flow resistivity, and result in a nonlinear [ital V]([ital j]) in the flux-flow regime.« less