c-Axis YBCO domains for current limiting applications

Isothermal growth of large YBaCuO single domains through an artificial array of holes

“…parallel to the eventual cracks, little attention has been paid to the oxygenation cracks, nearly seen as intrinsic to the material. But c-axis elements were shown recently to be very performing for current limitation [9], provided the cracks are suppressed, since the current is flowing in that case perpendicular to the cracks. By a progressive oxygenation process (details can be found in [10]), the oxygen gradients can be maintained below the limit where they induce cracks.…”

Diverging Giant Magnetoresistance in the Limit of Infinitely Conducting Spacer

“…Although one could attribute it to piling up of spin polarized quasiparticles in SC spacer, such interpretation would require a deeper understanding of c-axis transport in these structures where the CuO 2 planes are parallel to the magnetic layers. The observation of this effect in a low carrier density cuprate of the present study is much more intriguing because its c-axis resistivity is insulator-like in the normal state [12].…”

“…x ≥ 0.55, the system has an insulating and antiferromagnetc (AF) ground state [12]. The reduction in T c with x is presumed to be a consequence of lowering of the hole concentration and their mobility due to the out-ofplane disorder caused by Pr ions.…”

Growth of YBCO single domains through an array of holes for FCL c-axis superconducting elements

“…1,3 This necessary lowering of J c for safe transition has been the triggering opportunity to investigate another original configuration for current limitation: the use of YBaCuO single domain sample with currents flowing along c-axis. 4 This configuration leads to a more compact design of the current limiter elements thanks to a resistivity higher along c-axis than in (a, b) planes by two orders of magnitude. Electric fields up to 4000 V/m have been obtained with c-axis elements as compared to an average of 100 V/m with meanders.…”

“…In prototypes tested by the CRETA, the desired section (dictated by the nominal current to flow in the conductor) was obtained by assembling thin c-axis slabs of 1-1.5 mm in parallel using silver paste. 4 Such individual elements can fit preliminary test, but this assembly is delicate and time consuming. Furthermore, reproducibility is a major concern.…”