Transition to a superconductor with insulating cavitiesM. 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.
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