Kansas State University Physics
Research Experiences for Undergraduates Summer 2008
"Vortex switching in nanomagnetic structures"
Abstract---Due to long-range dipolar coupling, a thin nanomagnet of adequate size can support a single
vortex ground state. Placing one or more holes in the magnet, on which a vortex will be
pinned energetically, control over the vortex position and circulation can be obtained,
which can lead to designs for switching or memory devices. The REU project would involve
programming energy minimization and Monte Carlo simulations for this kind of model.
See the short introductory presentation to this topic.
Image at right: A strong current points into the page through the hole, causing reversal
of the circulation of the vortex pinned on the hole, by the production of both a positive and
negative vortex that exit the system! The initial circulation was counterclockwise. The currrent
forces clockwsie circulation to be lower energy. The spin configuration was produced by a
Monte Carlo simulation. ------>
Some Research Resources on Vortices in Magnetic Nanodots
- ``Influence of a perpendicular current on the circulation of a
pinned magnetic vortex,'' G. M. Wysin, for a special review book,
hole-vortex08.pdf (1.0 MB);
- ``Vortex--vacancy interactions in two-dimensional easy-plane magnets,''
Phys. Rev. B 68, 184411 (2003) [11 pages].
zipped RevTeX (73 kB);
v-v03.pdf (420 kB).
- ``Vortex rotation control in Permalloy disks with small circular voids,''
Vavasorri et al.,
J. Appl. Phys. 99, 053902 (2006).
- ``Dynamics of vortex core switching in ferromagnetic nanodisks,''
Xiao et al.,
Appl. Phys. Lett. 89, 262507 (2006).
- ``Stability of magnetic vortex in soft magnetic nano-sized cylinder,''
Metlov & Guslienko,
J. Mag. Magn. Mater. 242-245, 1015 (2002).
- ``Shifting and pinning of a magnetic vortex core in a Permalloy dot by a magnetic field,''
Uhlig et al.,
Phys. Rev. Lett. 95, 237205 (2005).
- ``Vortex polarity switching by a spin-polarized current,''
Caputo et al.,
Phys. Rev. Lett. 98, 056604 (2007).
- ``Effective anisotropy of thin nanomagnets: Beyond the surface-anisotropy approach,''
Caputo et al.,
Phys. Rev. B 76, 174428 (2007).
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Last update: Thursday May 22 2008.
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