We fabricate nanosized superconducting YBa(2)Cu(3)O(7-δ) (Y-123) and nonsuperconducting Y(2)BaCuO(5) (Y-211) powders using carbon nanotubes as template. The mean particle size of Y-123 and Y-211 is 12 and 30 nm, respectively. The superconducting transition temperature of the Y-123 nanopowder is 90.9 K, similar to that of commercial, micrometer-scale powders fabricated by conventional processing...

Many compounds based on CuO2 planes (cuprates) superconduct below a critical temperature Tc. Some of them show a second phase where a spontaneous static magnetic field appears below a critical temperature Tg, which is lower than Tc. By comparing Tc and Tg in numerous superconducting families, each with its own maximum Tc, we find that the same energy scale determines both critical temperatures....

Vortex lattice dynamics has been studied in thin Nb superconducting films sputtered on top of a dense triangular array of V dots with and without an intermediate SiO2 insulating layer. While the insulating layer modifies only slightly the Nb film corrugation, it reduces superconducting commensurability effects (CE) substantially. This implies that superconducting commensurability is dominated b...

– We investigated the pinning of flux lines in a superconducting film by a regular array of magnetic antidots. The sample consists of a Co/Pt multilayer with perpendicular magnetic anisotropy in which a regular pattern of submicron holes is introduced and which is covered by a type-II superconducting Pb film. The resulting ferromagnetic/superconducting heterostructure shows a pronounced asymmet...

The deleterious effects of disorder are amplified in lower dimensions, where long-range coherence is, at best, only marginally stable. A case in point is the destruction of superconductivity in ultrathin granular' and continuous metal films. The disorder is parametrized by the film sheet resistance and the data suggest a zero-temperature threshold for quenching global superconducting coherence ...

The accelerating gradient performance of superconducting niobium cavities is rapidly progressing as a result of reduced field emission due to improvement in surface preparation techniques. Beyond the field emission limitation, there exists a fundamental limit imposed by the critical magnetic field of niobium. One way to tackle this limit is to reduce the ratio of the peak magnetic field to the ...

– Based on the model of F/S/F trilayer with atomic thickness [A. Buzdin and M. Daumens, cond-mat/0305320] we discuss the relative roles of pair-breaking and proximity effects, as a function of the exchange field, of disorder and of a finite thickness in the su-perconducting layer. The exchange field can be small (weak ferromagnets) or large (strong ferromagnets) compared to the superconducting ...

The Ginzburg–Landau (GL) equations of superconductivity provide a computational model for the study of magnetic flux vortices in type-II superconductors. In this article we show through numerical examples and rigorous mathematical analysis that the GL model reduces to the frozen-field model when the charge of the Cooper pairs (the superconducting charge carriers) goes to zero while the applied ...