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Spin dynamics in magnetic vortex str...

Park, Jooho.

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Spin dynamics in magnetic vortex structures.

紀錄類型:	書目-電子資源 : Monograph/item
正題名/作者:	Spin dynamics in magnetic vortex structures./
作者:	Park, Jooho.
面頁冊數:	125 p.
附註:	Source: Dissertation Abstracts International, Volume: 66-04, Section: B, page: 2124.
Contained By:	Dissertation Abstracts International66-04B.
標題:	Physics, Condensed Matter. -
電子資源:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3172835
ISBN:	9780542099977

Spin dynamics in magnetic vortex structures.
Park, Jooho.

Spin dynamics in magnetic vortex structures. - 125 p.

Source: Dissertation Abstracts International, Volume: 66-04, Section: B, page: 2124.

Thesis (Ph.D.)--University of Minnesota, 2005.

This dissertation addresses spin dynamics in magnetic vortex structures, which have been experimentally investigated using time-resolved Kerr microscopy. This technique has been successfully implemented as a local spectroscopic probe to observe spin dynamics in geometrically confined magnetic structures with picosecond time resolution and spatial resolution on the order of a few hundred nanometers.

ISBN: 9780542099977Subjects--Topical Terms:

1018743
Physics, Condensed Matter.

Spin dynamics in magnetic vortex structures.
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245 1 0 $a Spin dynamics in magnetic vortex structures.
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500 $a Source: Dissertation Abstracts International, Volume: 66-04, Section: B, page: 2124.
500 $a Adviser: Paul Adams Crowell.
502 $a Thesis (Ph.D.)--University of Minnesota, 2005.
520 $a This dissertation addresses spin dynamics in magnetic vortex structures, which have been experimentally investigated using time-resolved Kerr microscopy. This technique has been successfully implemented as a local spectroscopic probe to observe spin dynamics in geometrically confined magnetic structures with picosecond time resolution and spatial resolution on the order of a few hundred nanometers.
520 $a Using electron-beam lithography, well-defined permalloy Ni81Fe19 disks with diameters in the range between 500 nm and 5 mum were fabricated. In the remnant state, permalloy disks form a flux-closure structure with a magnetic vortex core at the center of disk. The magnetization inside the core points out-of or into the disk plane. As the applied field decreases from a saturated state, the disks exhibit a distinct magnetization reversal process associated with the nucleation and subsequent annihilation of a magnetic vortex.
520 $a The motion of a magnetic vortex, a gyrotropic mode, is directly observed in real time and space. The observed eigenfrequencies of the vortex mode as a function of disk size are in a good agreement with micromagnetic simulations. They also fall close to the predictions of a theory in which the magnetization of the displaced vortex is assumed to deform so that there are no magnetostatic charges at the edge of the disk. It is also observed that the vortex-mode eigenfrequency is nearly independent of the in-plane applied field.
520 $a Azimuthal spin-wave modes, standing waves along the azimuthal direction in the vortex state, are investigated by exciting the spin system using an in-plane magnetic field pulse. Due to the cylindrical symmetry of the vortex state in remanence, two azimuthal modes propagating along opposite directions with the same number of azimuthal nodes are expected to be degenerate. However, our experimental results clearly demonstrate that the relative phase of the two azimuthal modes is determined by the polarity of the vortex core, and the magnitude of the splitting is of the same order as the vortex gyrotropic frequency. The broken degeneracy of the azimuthal spin-wave modes reveals how low-frequency excitations associated with domain structure influence spin-wave dynamics.
590 $a School code: 0130.
650 4 $a Physics, Condensed Matter. $3 1018743
650 4 $a Physics, Electricity and Magnetism. $3 1019535
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710 2 0 $a University of Minnesota. $3 676231
773 0 $t Dissertation Abstracts International $g 66-04B.
790 1 0 $a Crowell, Paul Adams, $e advisor
790 $a 0130
791 $a Ph.D.
792 $a 2005
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3172835