Vortex ratchet reversal at fractional matching fields in kagomelike array with symmetric pinning centers
Arrays of Ni nanodots embedded in Nb superconducting films have been fabricated by sputtering and electron-beam lithography techniques. The arrays are periodic triangular lattices of circular Ni dots arranged in a kagomélike pattern with broken reflection symmetry. Relevant behaviors are found in th...
| Autores: | , , , , , |
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| Formato: | artículo |
| Fecha de publicación: | 2010 |
| País: | España |
| Recursos: | Universidad Complutense de Madrid (UCM) |
| Repositorio: | Docta Complutense |
| Idioma: | inglés |
| OAI Identifier: | oai:docta.ucm.es:20.500.14352/42677 |
| Acesso em linha: | https://hdl.handle.net/20.500.14352/42677 |
| Access Level: | acceso abierto |
| Palavra-chave: | 538.9 Regular array Magnetic dots Films Lattice Física de materiales Física del estado sólido 2211 Física del Estado Sólido |
| Resumo: | Arrays of Ni nanodots embedded in Nb superconducting films have been fabricated by sputtering and electron-beam lithography techniques. The arrays are periodic triangular lattices of circular Ni dots arranged in a kagomélike pattern with broken reflection symmetry. Relevant behaviors are found in the vortex lattice dynamics: i at values lower than the first integer matching field, several fractional matching fields are present when the vortex lattice moves parallel or perpendicular to the reflection symmetry axis of the array showing a clear anisotropic character in the magnetoresistance curves, ii injecting an ac perpendicular to the reflection symmetry axis of the array yields an unidirectional motion of the vortex lattice ratchet effect as a result of the interaction between the whole vortex lattice and the asymmetric lattice of dots, iii increasing the input current amplitudes the ratchet effect changes polarity independently of matching field values. These experimental results can be explained taking into account the vortex lattice density. |
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