Scanning SQUID microscope study of vortex polygons and shells in weak-pinning disks of an amorphous superconducting film

Physical Review B - Condensed Matter and Materials Physics

Volumn 82, Issue 1, 2010, Pages

  Kokubo, Nobuhito ^a   Okayasu, Satoru ^b   Kanda, Akinobu ^c   Shinozaki, Bunju ^a  

^a KYUSHU UNIVERSITY   (Japan)

^b JAPAN ATOMIC ENERGY AGENCY   (Japan)

^c UNIVERSITY OF TSUKUBA   (Japan)

Author keywords

[No Author keywords available]

Indexed keywords

EID: 77956525296     PISSN: 10980121     EISSN: 1550235X     Source Type: Journal    
DOI: 10.1103/PhysRevB.82.014501     Document Type: Article

References (34)

1. A. A. Abrikosov, Sov. Phys. JETP 5, 1174 (1957).
2. A. I. Buzdin and J. P. Brison, Phys. Lett. A 196, 267 (1994). 10.1016/0375-9601(94)91083-9
3. P. A. Venegas and E. Sardella, Phys. Rev. B 58, 5789 (1998). 10.1103/PhysRevB.58.5789
4. J. J. Palacios, Phys. Rev. Lett. 84, 1796 (2000). 10.1103/PhysRevLett.84. 1796
5. B. J. Baelus, L. R. E. Cabral, and F. M. Peeters, Phys. Rev. B 69, 064506 (2004). 10.1103/PhysRevB.69.064506
6. L. R. E. Cabral, B. J. Baelus, and F. M. Peeters, Phys. Rev. B 70, 144523 (2004). 10.1103/PhysRevB.70.144523
7. V. R. Misko, B. Xu, and F. M. Peeters, Phys. Rev. B 76, 024516 (2007). 10.1103/PhysRevB.76.024516
8. L. F. Chibotaru, A. Ceulemans, V. Bruyndoncx, and V. V. Moshchalkov, Nature (London) 408, 833 (2000). 10.1038/35048521
9. L. F. Chibotaru, A. Ceulemans, V. Bruyndoncx, and V. V. Moshchalkov, Phys. Rev. Lett. 86, 1323 (2001). 10.1103/PhysRevLett.86.1323
10. E. Y. Yarmchuk and R. E. Packard, J. Low Temp. Phys. 46, 479 (1982). 10.1007/BF00683912
11. K. W. Madison, F. Chevy, W. Wohlleben, and J. Dalibard, Phys. Rev. Lett. 84, 806 (2000). 10.1103/PhysRevLett.84.806
12. A. K. Geim, I. V. Grigorieva, S. V. Dubonos, J. G. S. Lok, J. C. Maan, A. E. Filippo, and F. M. Peeters, Nature (London) 390, 259 (1997). 10.1038/36797
13. A. K. Geim, S. V. Dubonos, J. J. Palacios, I. V. Grigorieva, M. Henini, and J. J. Schermer, Phys. Rev. Lett. 85, 1528 (2000). 10.1103/PhysRevLett.85. 1528
14. A. Kanda, B. J. Baelus, F. M. Peeters, K. Kadowaki, and Y. Ootuka, Phys. Rev. Lett. 93, 257002 (2004). 10.1103/PhysRevLett.93.257002
15. Y. Hata, J. Suzuki, I. Kakeya, K. Kadowaki, A. Odawara, A. Nagata, S. Nakayama, and K. Chinone, Physica C 388-389, 719 (2003). 10.1016/S0921-4534(02) 02503-0
16. T. Nishio, S. Okayasu, J. Suzuki, and K. Kadowaki, Physica C 412-414, 379 (2004). 10.1016/j.physc.2004.02.190
17. T. Nishio, Q. Chen, W. Gillijns, K. De Keyser, K. Vervaeke, and V. V. Moshchalkov, Phys. Rev. B 77, 012502 (2008). 10.1103/PhysRevB.77.012502
18. M. R. Connolly, M. V. Milosevic, S. J. Bending, J. R. Clem, and T. Tamegai, Europhys. Lett. 85, 17008 (2009). 10.1209/0295-5075/85/17008
19. I. V. Grigorieva, W. Escoffier, J. Richardson, L. Y. Vinnikov, S. Dubonos, and V. Oboznov, Phys. Rev. Lett. 96, 077005 (2006). 10.1103/PhysRevLett.96.077005
20. H. J. Zhao, V. R. Misko, F. M. Peeters, V. Oboznov, S. V. Dubonos, and I. V. Grigorieva, Phys. Rev. B 78, 104517 (2008). 10.1103/PhysRevB.78.104517
21. I. V. Grigorieva, W. Escoffier, V. R. Misko, B. J. Baelus, F. M. Peeters, L. Y. Vinnikov, and S. V. Dubonos, Phys. Rev. Lett. 99, 147003 (2007). 10.1103/PhysRevLett.99.147003
22. J. R. Kirtley, M. B. Ketchen, K. G. Stawiasz, J. Z. Sun, W. J. Gallagher, S. H. Blanton, and S. J. Wind, Appl. Phys. Lett. 66, 1138 (1995). 10.1063/1.113838
23. J. Pearl, Appl. Phys. Lett. 5, 65 (1964). 10.1063/1.1754056
24. We estimate λ with the dirty-limit expression described in P. H. Kes and C. C. Tsuei, Phys. Rev. B 28, 5126 (1983) 10.1103/PhysRevB.28.5126
25. the coherence length ξ (0) is estimated by ξ (0) = √ Φ 0 / 2 π H c 2 (0) with the second critical field H c 2 (0) at T = 0.
26. B. L. T. Plourde, D. J. Van Harlingen, N. Saha, R. Besseling, M. B. S. Hesselberth, and P. H. Kes, Phys. Rev. B 66, 054529 (2002). 10.1103/PhysRevB.66. 054529
27. V. G. Kogan, V. V. Dobrovitski, J. R. Clem, Y. Mawatari, and R. G. Mints, Phys. Rev. B 63, 144501 (2001). 10.1103/PhysRevB.63.144501
28. The rms flux noise for our system referred to the pick-up loop is ∼ 5 m Φ 0 per pixel in the images.
29. F. Tafuri, J. R. Kirtley, P. G. Medaglia, P. Orgiani, and G. Balestrino, Phys. Rev. Lett. 92, 157006 (2004). 10.1103/PhysRevLett.92.157006
30. T. Nishio, S. Okayasu, J. I. Suzuki, N. Kokubo, and K. Kadowaki, Phys. Rev. B 77, 052503 (2008). 10.1103/PhysRevB.77.052503
31. We note that the observed orientations are some of the metastable states stabilized by subtle uneven boundary confinement due to the edge roughness and/or possible weak bulk pinning in the disk. Otherwise, during the scanning, the orientation can be aligned along the scan direction of the pick-up loop due to the weak coupling between the loop and the vortices.
32. Repeated field-cool measurements at the same magnetic fields show nearly identical vortex configurations, including the orientation of the patterns, when the vorticity is unchanged.
33. We emphasize that the pinning site accommodates only one vortex and others are distributed around in the disk. This is distinct from phenomena observed in the micrometer-sized Nb mesas, where multifluxons are observed near the strong pinning site (Ref.).
34. The pinning site at the disk center can be found from a vortex pattern at L = 2.