Yoshihisa Ozono

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.

Transport properties of SrxCuO2-σ film in YBCO/SrxCuO2-σ/YBCO system

Abstract The zero resistance behavior of a SrxCuO2-σ film sandwiched with YBa2Cu3O7−z films has been examined. The transition temperatures of the sandwiched-type-SrxCuO2-δ, which was deposited optimally at x=0.1 and with thickness ≈2200A, was Tc-end=93.8K and Tc-on=99.0K.

Fabrication and superconductivity of YBCO/CuO/YBCO films

The AC susceptibility of a CuO film sandwiched with YBa2Cu3O7−δ (YBCO) films has been examined. The trilayer films are fabricated on a SrTiO3 substrate by using in-situ DC magnetron sputtering. The superconducting transition of AC susceptibility of the CuO sandwiched with YBCO reached the onset temperature of 94.0K followed by the end of transition at 92.5K. The critical temperature for the zero resistivity of YBCO electrodes in this trilayer sample was 88.1K. The thin CuO layer with the thickness of ∼300Å was speculated to have defects induced with diffusion of Ba from YBCO. The chemical shifts of ∼1eV was observed in the binding energy of Ba3d5/2 from that of both YBCO and BaO by X-ray photoemission spectroscopy.