Electrical conduction mechanisms of metal/high-T-c superconductor (YBCO) interfaces



: Lanosa LF, Huhtinen H, Paturi P, Acha C

Publisher: IOP PUBLISHING LTD

: 2020

: Journal of Physics: Condensed Matter

: JOURNAL OF PHYSICS-CONDENSED MATTER

: J PHYS-CONDENS MAT

: ARTN 175001

: 32

: 17

: 9

: 0953-8984

: 1361-648X

DOI: https://doi.org/10.1088/1361-648X/ab6b8b


Current-voltage characteristics of Au/YBa2Cu3O interfaces (Au/YBCO), built on optimally-doped YBCO thin films, grown by pulsed laser deposition, were measured as a function of temperature in the 50 K to 270 K range, for two different resistance states. A non-trivial equivalent circuit model is proposed, which reveals the existence of a highly inhomogeneous scenario composed by two complex layers: one presenting both a non-linear Poole-Frenkel conduction as well as variable range hopping localization effects (probably associated with YBa2Cu3O6) mixed with a minor metallic phase, while the other is also composed by a mixture of YBCO with different oxygen contents, where a metallic ohmic phase still percolates. A microscopic description of the effects produced by the resistance switching is given, showing the evolution of carrier traps, localization effects and dielectric behavior for each state. The dielectric behavior is interpreted in terms of a Maxwell-Wagner scenario.



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