Fractal vortices in disordered superconductors

A. Raboutou, P. Peyral, C. Lebeau, J. Rosenblatt, J.P. Burin and Y. Fouad

Physica A: Statistical Mechanics and its Applications, 1994, vol. 207, issue 1, 271-279

Abstract: We measure the low-frequency magnetic response χ = χ′ + iχ″ of halogenated ceramics YBa2Cu3O7−δFx as functions of x, AC field amplitude H0 and temperature T. The field of first flux penetration displays scaling behaviour: H1(x, T) = H1(x, 0) (1 − T/Tc)ζ, with Tc the coherence temperature and ζ = 2.7 ± 0.2; in all cases H1 ⪢ Hc1 expected for the ideal material. A model where deviations from stoichiometry are assumed to result in local critical temperatures Tc(r), is described. Superconductivity is due to regions where T< Tc(r) with concentration p(T). The coherence temperature is defined by p(Tc) = pc, the percolation threshold. Critical exponents appear to be related to percolation exponents, in particular ν = 2νp/3βp≅ 1.33, in agreement with the experimental value found in granular superconductors. Expressions are found for the magnetic fields observed in Euclidean space while being due to currents restricted to fractal percolation clusters. The free energy of the resulting fractal vortices accounts for the experimental value of the exponent in the temperature dependence of H1(T).

Date: 1994
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (1)

Downloads: (external link)
http://www.sciencedirect.com/science/article/pii/0378437194903840
Full text for ScienceDirect subscribers only. Journal offers the option of making the article available online on Science direct for a fee of $3,000

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:eee:phsmap:v:207:y:1994:i:1:p:271-279

DOI: 10.1016/0378-4371(94)90384-0

Access Statistics for this article

Physica A: Statistical Mechanics and its Applications is currently edited by K. A. Dawson, J. O. Indekeu, H.E. Stanley and C. Tsallis

More articles in Physica A: Statistical Mechanics and its Applications from Elsevier
Bibliographic data for series maintained by Catherine Liu ().