Europhys. Lett.
Volume 67, Number 3, August 2004
Page(s) 446 - 452
Section Condensed matter: electronic structure, electrical, magnetic, and optical properties
Published online 01 July 2004
Europhys. Lett., 67 (3), pp. 446-452 (2004)
DOI: 10.1209/epl/i2004-10072-2

Transition to a superconductor with insulating cavities

M. M. Doria and A. R. de C. Romaguera

Instituto de Física, Universidade Federal do Rio de Janeiro C.P. 68528, 21941-972, Rio de Janeiro RJ, Brasil

(Received 12 March 2004; accepted in final form 17 May 2004)

An extreme type-II superconductor with internal insulating regions, namely cavities, is studied here. We find that the cavity-bearing superconductor has lower energy than the defect-free superconductor above a critical magnetic induction B* for insulating cavities but not for metallic ones. Using a numerical approach for the Ginzburg-Landau theory, we compute and compare free energy densities for several cavity radii and at least for two cavity densities, assuming a cubic lattice of spherical cavities.

74.20.De - Phenomenological theories (two-fluid, Ginzburg-Landau, etc.).
74.25.-q - Properties of type-I and type-II superconductors.
74.81.-g - Inhomogeneous superconductors and superconducting systems.

© EDP Sciences 2004