Field percolation and high current density in 80/20 DyBa2Cu3O7 − x/Dy2BaCuO5 bulk magnetically textured composite ceramics

Abstract

Abstract:We measured the AC susceptibility of magnetically textured (123) 80%/211(20%) DyBaCuO composite in a special set-up in order to enhance the intergrain contribution. The synthesis process led to very clean "weak links" at grain boundaries. At the percolation threshold bulk shielding paths were such that the intergrain critical current density J C was above 10 5 A/cm 2 . The field dependence of J C was understood through an analytical form indicating a distribution of currents similar to the law of clusters at fracture/percolation thresholds.

The isothermal melt-texturing of bulk YBa2Cu3O7-xceramics: from cooking to modelling

“…The presence of these secondary phases at the grain boundaries is a major impediment for the obtention of high J c values. Indeed, these non-superconducting phases drastically decrease the intragrain current density [32]. This intrinsic feature should thus be understood and practical rules to avoid such foreign phases should be searched for.…”

Magneto-transport characterization of Dy123 monodomain superconductors

“…In the case of systems belonging to the YBCO-123 class, the Dy123 superconductor is of interest because the magnetic moment borne by D y atoms enables a very successful technique, i.e. magnetic texturing in external magnetic field [11][12][13] in order to produce the well aligned samples. Another technique recently used to grow large pieces of superconducting ceramics has been the seeding method.…”

AC susceptibility data on Dy2O3 seeded randomly oriented Dy-123 mono domains melt-textured superconductor

“…Usually a shoulder is predicted when weak links are present. This shoulder generally allows to deduce both intergranular (J cj ) and intragranular (J cg ) critical current densities from the slopes of the flux profile on both sides of the shoulder [4][5][6]. This is not the case here, where flux profiles are rather linear.…”