The ac effect of vortex pinning in the arrays of defect sites on Nb films

T. C. Wu, Lance Horng, J. C. Wu, C. W. Hsiao, Jan Koláček, T. J. Yang

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

Niobium thin films with spacing-graded array of submicrometer-scaled holes had been fabricated using electron beam lithography through a lift-off technique. The magnetoresistance measurements and current-voltage characteristics were carried out with the external magnetic field applied perpendicular to the film plane, in which commensurable effects were observed in both experiments. The magnetoresistance with positive/negative directions of dc current revealed identical curves except the dips at matching fields separated. Two distinct current-voltage curves, which resulted from the positive and negative applied current directions, respectively, were discerned when the external magnetic field was fixed at the matching field, which is believed to be due to asymmetry pinning potential in the spacing-graded array of holes. In addition, ac current-voltage curve measured at matching field showed a ratchet bump along with another extra peak associated with incommensurable effect.

Original languageEnglish
Article number08M515
JournalJournal of Applied Physics
Volume99
Issue number8
DOIs
Publication statusPublished - 2006 May 25

Fingerprint

vortices
defects
electric potential
curves
spacing
magnetic fields
niobium
lithography
asymmetry
electron beams
thin films

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy(all)

Cite this

Wu, T. C. ; Horng, Lance ; Wu, J. C. ; Hsiao, C. W. ; Koláček, Jan ; Yang, T. J. / The ac effect of vortex pinning in the arrays of defect sites on Nb films. In: Journal of Applied Physics. 2006 ; Vol. 99, No. 8.
@article{a0dd88b91a3b44beb4dbc40d8d353e53,
title = "The ac effect of vortex pinning in the arrays of defect sites on Nb films",
abstract = "Niobium thin films with spacing-graded array of submicrometer-scaled holes had been fabricated using electron beam lithography through a lift-off technique. The magnetoresistance measurements and current-voltage characteristics were carried out with the external magnetic field applied perpendicular to the film plane, in which commensurable effects were observed in both experiments. The magnetoresistance with positive/negative directions of dc current revealed identical curves except the dips at matching fields separated. Two distinct current-voltage curves, which resulted from the positive and negative applied current directions, respectively, were discerned when the external magnetic field was fixed at the matching field, which is believed to be due to asymmetry pinning potential in the spacing-graded array of holes. In addition, ac current-voltage curve measured at matching field showed a ratchet bump along with another extra peak associated with incommensurable effect.",
author = "Wu, {T. C.} and Lance Horng and Wu, {J. C.} and Hsiao, {C. W.} and Jan Kol{\'a}ček and Yang, {T. J.}",
year = "2006",
month = "5",
day = "25",
doi = "10.1063/1.2176143",
language = "English",
volume = "99",
journal = "Journal of Applied Physics",
issn = "0021-8979",
publisher = "American Institute of Physics Publising LLC",
number = "8",

}

The ac effect of vortex pinning in the arrays of defect sites on Nb films. / Wu, T. C.; Horng, Lance; Wu, J. C.; Hsiao, C. W.; Koláček, Jan; Yang, T. J.

In: Journal of Applied Physics, Vol. 99, No. 8, 08M515, 25.05.2006.

Research output: Contribution to journalArticle

TY - JOUR

T1 - The ac effect of vortex pinning in the arrays of defect sites on Nb films

AU - Wu, T. C.

AU - Horng, Lance

AU - Wu, J. C.

AU - Hsiao, C. W.

AU - Koláček, Jan

AU - Yang, T. J.

PY - 2006/5/25

Y1 - 2006/5/25

N2 - Niobium thin films with spacing-graded array of submicrometer-scaled holes had been fabricated using electron beam lithography through a lift-off technique. The magnetoresistance measurements and current-voltage characteristics were carried out with the external magnetic field applied perpendicular to the film plane, in which commensurable effects were observed in both experiments. The magnetoresistance with positive/negative directions of dc current revealed identical curves except the dips at matching fields separated. Two distinct current-voltage curves, which resulted from the positive and negative applied current directions, respectively, were discerned when the external magnetic field was fixed at the matching field, which is believed to be due to asymmetry pinning potential in the spacing-graded array of holes. In addition, ac current-voltage curve measured at matching field showed a ratchet bump along with another extra peak associated with incommensurable effect.

AB - Niobium thin films with spacing-graded array of submicrometer-scaled holes had been fabricated using electron beam lithography through a lift-off technique. The magnetoresistance measurements and current-voltage characteristics were carried out with the external magnetic field applied perpendicular to the film plane, in which commensurable effects were observed in both experiments. The magnetoresistance with positive/negative directions of dc current revealed identical curves except the dips at matching fields separated. Two distinct current-voltage curves, which resulted from the positive and negative applied current directions, respectively, were discerned when the external magnetic field was fixed at the matching field, which is believed to be due to asymmetry pinning potential in the spacing-graded array of holes. In addition, ac current-voltage curve measured at matching field showed a ratchet bump along with another extra peak associated with incommensurable effect.

UR - http://www.scopus.com/inward/record.url?scp=33646718327&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=33646718327&partnerID=8YFLogxK

U2 - 10.1063/1.2176143

DO - 10.1063/1.2176143

M3 - Article

AN - SCOPUS:33646718327

VL - 99

JO - Journal of Applied Physics

JF - Journal of Applied Physics

SN - 0021-8979

IS - 8

M1 - 08M515

ER -