Browsing by Author "Lin, YA"

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Current detection of vortex motion in patterned S-shape wires with constrictions
(2006-04-15)
Chen, YC
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Yao, YD
;
Lee, SF
;
Lin, YA
;
Chen, DC
The current-driven effect on the vortex domain wall in a series-connected permalloy S-shape patterns was investigated. When a domain wall is initially formed in the wire section, in contrast to the ac result, applying a low dc current (J similar to 10(5) A/cm(2)) will break the degeneracy of the switching energy in different connected sections. Moreover, three kinds of effects on vortex states are observed by applying a high dc current (J similar to 10(7) A/cm(2)). The current applied slightly below the original switching field will drive vortices to constrictions while the current applied far below the original switching field will only perturb the vortex to another stable state. At the fields slightly over the original switching field, the domain walls are initially trapped at constrictions, injecting current will cause both the depinning and deformation of vortices. (C) 2006 American Institute of Physics.
Current-assisted magnetization switching in submicron permalloy S-shape wires with narrow junctions
(2005-05-15)
Chen, YC
;
Lin, YA
;
Chen, DC
;
Yao, YD
;
Lee, SF
We report the results of the current-assisted magnetization switching in submicron permalloy S-shape wires with narrow junctions (or notches). Domain walls were initially formed and pinned in the vicinity of the notches. Two distinct behaviors are observed in the current-assisted magnetization reversal process. When the applied field is near switching field (Delta H < 7 Oe), the injected current directly switched the wire magnetization, and the needed critical current varied linearly and significantly with the field intensity. In contrast, when the field is relatively far from the switching field (Delta H > 7 Oe), the current only moves the domain wall to a local stable state, and the critical current varied slightly with the field. Moreover, two resistance jumps during current scanning are observed in the cases with magnetization reversals. These results reveal that the current driven effect is closely related to the initial domain states, and are explained by a theoretical model based on spin transfer effect. (c) 2005 American Institute of Physics.