Chimie douce route to hetero-structured high-T_c cuprates

Inorganic-inorganic and organic-inorganic hetero-structured high-T_c superconductors were achieved through a chimie douce (mild chemistry) route, in which inorganic or organic components were incorporated into the copper oxide superconductors, Bi₂Sr₂Ca_m-1Cu_mO_y (m=1, 2, and 3; BSCCO). According to the physico-chemical analyses for these nanohybrid materials, it is suggested that the high-T_c superconductivity is an intrinsic two-dimensional property of the copper oxide plane. All of these hetero-structured nanohybrid materials have an unique structural feature of a superconducting-insulating-superconducting (S-I-S) multilayer with atomically clean interfaces. Especially, the organic-inorganic nanohybrid is expected to be a promising precursor for superconducting colloidal suspension or nanoparticles, which could be applied to the fabrication of superconducting films or wires.