A New Superconducting Cuprate Prepared by Low-Temperature Thin-Film Synthesis

A new superconducting cuprate was synthesized in a Ba-Cu-O system by low-temperature thin-film growth with reactive coevaporation. The superconducting phase is obtained only after strong oxidization by ozone following the growth. Structural analyses, based on X-ray diffraction and high resolution electron microscopy, suggests that the superconducting phase is represented by Ba2CuO3+δ [02(n-l)n–Ba, n=l] with the K2NiF4-based structure. The resistivity measurement shows Tc onset ≈ 60–70 K and Tc end≤ 47 K, and the magnetic measurement shows Tc onset ≈ 85–90 K.