Enhanced superconductivity of YBCO interfaces: origin of high critical temperature in layered superconductors

TL;DR

This study investigates how interfaces and surface modifications in YBCO superconductors influence their critical temperatures, revealing that layered structures and silver overlays can enhance superconductivity.

Contribution

It demonstrates that interface and surface treatments in YBCO films can increase Tc, suggesting a general mechanism for high-temperature superconductivity in layered systems.

Findings

Interface Tc exceeds surface Tc in YBCO films.

Silver overlay further enhances Tc.

Layered microstructure is key to high Tc.

Abstract

Superconducting transition temperatures Tc of the YBCO film surface and of the YBCO film/substrate interface were measured inductively. It was observed that the interface- Tc is always higher then the surface - Tc. However deposition of silver over-layer enhances the superconducting transition temperatures. This observation was confirmed by four-point resistance measurements. In the annealed YBCO/Ag bilayers magnetic properties of the interface were observed. We believe that such phenomena are a common feature of layered systems. This two dimensional structure reminds the layered microstructure of the high-temperature superconductors and one can suppose that covering of the superconducting layer by non-superconducting layer is a condition for obtaining high critical temperatures in general.