Very large purely intralayer critical current density in ultrathin cuprate artificial structures

Ultrathin artificial high temperature superconducting structures, consisting of (Ba0.9Nd0.1)CuO2+x and CaCuO2 layers, were grown by pulsed laser deposition. Intralayer superconductivity at 60 K was obtained for a structure consisting of a single (CaCuO2) block sandwiched between two (Ba0.9Nd0.1)CuO2+x charge reservoir blocks. The purely intralayer critical current density was measured at 4.2 K and resulted to be larger than 10(8) A/cm(2). These findings clearly show that interaction between nearest neighbor (CaCuO2) layers is not essential for high T-c superconductivity and strongly supports the physical model based on the idea that intralayer interaction alone is responsible for high temperature superconductivity.