Browsing by Author "Chiang, T. W."

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Demonstration of edge roughness effect on the magnetization reversal of spin valve submicron wires
(2010-07-12)
Chiang, T. W.
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Chang, L. J.
;
Yu, C.
;
Huang, S. Y.
;
Chen, D. C.
We prepared submicron wide trilayer spin valve wires designed with periodic "spikes" as artificial roughness. The height and the pitch of the spikes were varied systematically. No obvious dependence was found between the roughness and the domain wall velocity when the spikes were smaller than a threshold of 30 nm for NiFe. The average velocity was slowed down when the height of the spikes were larger than the threshold. In-plane transverse magnetic fields help to reduce the critical current density for current induced domain-wall motion. Our results could be attributed to the space modulation of the local magnetization. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3463459]
Properties of superconductivity for decoupled ferromagnet/superconductor trilayers and multilayers in Fe/Nb system
(2006-09-01)
Huang, S. Y.
;
Lee, S. F.
;
Liang, Jun-Jih
;
Yu, C. Y.
;
You, K. L.
The transition temperature T(c) and upper critical field H(c2) of sputtered Fe/Nb trilayers and multilayers have been determined by measurement of electrical resistivity. For a fixed Fe layer thickness, T(c) decreases with decreasing Nb thickness up to a critical thickness d(Nb)(crit) approximate to 34 nm below which superconductivity vanishes. When the superconducting layers are thin (d(Nb) < 140 nm) and decoupled by pair breaking in the ferromagnetic layers, the parallel critical field exhibits nonlinear temperature dependence, revealing a change in the superconducting dimensionality. The strong decrease of T(c) with decreasing Nb thickness as well as the temperature dependence of H(c2) can be well described by theoretical model. (C) 2006 Elsevier B. V. All rights reserved.