Oriented high T c superconductive layers on silver by devitrification of glasses formed in the Bi-Sr-Ca-Cu oxide system

Highly oriented crystalline layers of Bi4(Sr,Ca)3Cu4O16+x high Tc superconductors were produced by the devitrification of aerosol suspensions of glasses prepared from the mixed oxides when the suspensions were brought into rapid contact with heated silver substrates. The best magnetic susceptibility signals, produced by superconductivity at 77 K, were obtained when the glass was rapidly heated to about 850 °C from room temperature. The deposited layers are composed of a nearly pure superconductive phase in the form of flat platelets up to several hundred microns in diameter that are oriented with the c axis normal to the substrate. The addition of a small amount of Pb to the glass lowers the optimum deposition temperature and improves the crystal morphology.