Pinning of spiral fluxons by giant screw dislocations in YBa2Cu3O7 - δ single crystals: Josephson analog of the fishtail effect

S. Sergeenkov, L. Cichetto, Victor Anthony Garcia Rivera, C. Stari, E. Marega, C. A. Cardoso, F. M. Araujo-Moreira

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By using a highly sensitive homemade AC magnetic susceptibility technique, the magnetic flux penetration has been measured in YBa2Cu3O7 - δ single crystals with giant screw dislocations (having the structure of the Archimedean spirals) exhibiting a = 3 spiral turnings, the pitch b = 18.7 μm and the step height c = 1.2 nm (the last parameter is responsible for creation of extended weak-link structure around the giant defects). The magnetic field applied parallel to the surface enters winding around the weak-link regions of the screw in the form of the so-called spiral Josephson fluxons characterized by the temperature dependent pitch bf(T). For a given temperature, a stabilization of the fluxon structure occurs when bf(T) matches b (meaning an optimal pinning by the screw dislocations) and manifests itself as a pronounced low-field peak in the dependence of the susceptibility on magnetic field (applied normally to the surface) in the form resembling the high-field (Abrikosov) fishtail effect.

Original languageEnglish
Pages (from-to)30-34
Number of pages5
JournalJETP Letters
Issue number1
StatePublished - Mar 2010
Externally publishedYes

Bibliographical note

Funding Information:
This work has been financially supported by the Brazilian agencies CNPq, CAPES and FAPESP.

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