Superconductivity of SrxCuO2-δ Film in YBCO/SrxCuO2-δ/YBCO System

The zero resistance behavior of a SrxCuO2-δ film (x=0.05 ~ 1.0) sandwiched between YBa2Cu3O7-z film was examined. The highest transition temperatures of the sandwiched-type-SrxCuO2-δ, which was deposited optimally at x=0.1 and with a thickness ≈2200 A, was Tc-end = 93.8 K and Tc-onset = 99.0 K. In the region of x=0.05 ~ 1.0, the scattering order of Tc tended to decrease with increase of x, and the resistivity in a normal state had a minimum value at x=0.1. XRD exhibited a phase transformation of a infinite layer type (at x=1.0)-to-NaCl type like C/2c (at x=0.1). It was determined by XPS that Sr-3d5/2,3/2 core lines were the same value for both concentrations of x=1.0 and 0.1 in SrxCuO2-δ.