Superconducting artificial multilayers based on (Ba,Ca)/CuO[sub 2] grown by pulsed laser ablation

Superconducting multilayers, whose growth and structure are determined by the kinetic deposition and not by thermodynamics, are a powerful tool for investigating High Tc superconductors (HTSC) properties and for possible future applications. By means of Pulsed Laser Deposition (PLD), we grew such materials alternating infinite layer phases both pure and doped, to supply CuO2 planes and charge reservoir (CR) blocks respectively. We found out that using CR chemically doped with high concentrations of Ag and Sc substituted on the copper site in infinite layer compounds leads to a semiconducting behavior, whereas oxygen doping seems to be much more effective, since the BaCuO2 infinite phase, grown in high oxygen partial pressure, does actually bring about a superconducting behavior. We deposited BaCuO2/CaCuO2 superlattices with various periodicities and studied their transport and structural properties. By varying the deposition parameters, we reached both kinetic and thermodynamic growth and we observed semiconducting and superconducting behaviors.