Very large purely intralayer critical current density in ultrathin cuprate artificial structures.
Ultrathin artificial high temperature superconducting structures, consisting of (Ba(0.9)Nd0.1)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 (Ba(0.9)Nd0.1)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.