A NEW SUPERCONDUCTING CUPRATE PREPARED BY LOW-TEMPERATURE THIN-FILM SYNTHESIS IN A BA-CU-O SYSTEM

A new high-T-c superconducting cuprate composed of Ba, Cu and O was pr epared on SrTiO3(001) substrate by reactive coevaporation. The superco nducting phase is formed only in the limited temperature range between 575 and 625 degrees C and in a narrow compositional range. Observatio ns of the X-ray diffraction and transmission electron microscopy sugge sts that the superconducting phase is the 214-based structure. Superco nductivity is obtained only after strong oxidation after film growth. The resistivity measurement shows T-c(onset) approximate to 60 to 70 K and T-c(end) less than or equal to 38 K and the magnetic measurement shows T-c(onset) approximate to 85 to 90 K.