YBa2Cu3O7−δ-Ag-Al/Al2O3/Pb tunnel junctions based on the superconducting proximity effect

Abstract

YBa2Cu3O7−δ-Ag-Al/Al2O3/Pb superconducting tunnel junctions with high subgap resistance were fabricated using the proximity effect induced superconductivity in the Ag-Al layer by the YBa2Cu3O7−δ film. At low temperature an energy gap of 9–10 meV is found to be induced in the aluminum layer. Above 20 K the induced gap disappears mainly due to the decreased normal metal coherence length. At higher voltages (V≤120 meV) the dynamic conductance dI/dV∝V, characteristic for the normal tunneling density of states of the oxide superconductor.

Topological superconductivity and Majorana fermions in hybrid structures involving cuprate high-Tcsuperconductors

“…Experimentally, proximity effect was found to be weaker in the c-axis direction than in the ab-plane direction due to a much shorter co-herence length in the former direction. [89][90][91] We note, however, that so-called giant proximity effect has been reported both in the ab-plane [92][93][94][95] and c-axis 96 directions. Proximity effect in HTSC-ferromagnet and/or HTSC-half-metal heterostructures have also been studied experimentally.…”

Anomalous Proximity Effect in Gold Coated (110)YBa2Cu3O7Asulin1, Sharoni2, Yulli3 et al. 2004Phys. Rev. Lett.151100View full textAdd to dashboardCite

“…This facet-selectivity reflects the in plane versus out of plane anisotropy in the cuprate superconductors, which was also measured indirectly by other groups [8,9,10]. However, the proximity-induced order parameter decayed exponentially in a way typical of conventional N-S proximity systems.…”

Proximity Effect in Gold-CoatedYBa2Cu3O7−Sharoni1, Asulin2, Koren3 et al. 2004Phys. Rev. Lett.286380View full textAdd to dashboardCite

“…For example, Josephson coupling was observed in hightemperature S-N-S junctions when the normal to the junction plane was along the a axis (transport into the a-b plane), but not when it was along the c axis (transport perpendicular to the a-b plane) [8,9]. This implies that Cooper pairs can leak into N only along the CuO 2 planes.…”