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(Referência obtida automaticamente do Web of Science, por meio da informação sobre o financiamento pela FAPESP e o número do processo correspondente, incluída na publicação pelos autores.)

Magnetic flux penetration in Nb superconducting films with lithographically defined microindentations

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Autor(es):
Brisbois, J. [1] ; Adami, O. -A. [1] ; Avila, J. I. [1] ; Motta, M. [2] ; Ortiz, W. A. [2] ; Nguyen, N. D. [1] ; Vanderbemden, P. [3, 4] ; Vanderheyden, B. [3, 4] ; Kramer, R. B. G. [5] ; Silhanek, A. V. [1]
Número total de Autores: 10
Afiliação do(s) autor(es):
[1] Univ Liege, Dept Phys, B-4000 Sart Tilman Par Liege - Belgium
[2] Univ Fed Sao Carlos, Dept Fis, BR-13565905 Sao Carlos, SP - Brazil
[3] Univ Liege, SUPRATECS, B-4000 Sart Tilman Par Liege - Belgium
[4] Univ Liege, Dept Elect Engn & Comp Sci, B-4000 Sart Tilman Par Liege - Belgium
[5] Univ Grenoble 1, CNRS, Inst Neel, F-38042 Grenoble 9 - France
Número total de Afiliações: 5
Tipo de documento: Artigo Científico
Fonte: Physical Review B; v. 93, n. 5 FEB 23 2016.
Citações Web of Science: 18
Resumo

We present a thorough investigation by magneto-optical imaging of the magnetic flux penetration in Nb thin films with lithographically defined border indentations. We demonstrate that discontinuity lines (d lines), caused by the abrupt bending of current streamlines around the indentations, depart from the expected parabolic trend close to the defect and depend on the shape and size of the indentation as well as on the temperature. These findings are backed up and compared with theoretical results obtained by numerical simulations and analytical calculations highlighting the key role played by demagnetization effects and the creep exponent n. In addition, we show that the presence of nearby indentations and submicrometer random roughness of the sample border can severely modify the flux front topology and dynamics. Strikingly, in contrast to what has been repeatedly predicted in the literature, we do not observe that indentations act as nucleation spots for flux avalanches, but they instead help to release the flux pressure and avoid thermomagnetic instabilities. (AU)

Processo FAPESP: 07/08072-0 - Pesquisa fundamental em supercondutividade e magnetismo - sistemas com potencial para aplicações: óxidos avançados e supercondutores dotados de estruturas artificiais
Beneficiário:Wilson Aires Ortiz
Linha de fomento: Auxílio à Pesquisa - Temático