Synthesis and characterization of the infinite-layer superconductor Sr0.9La0.1CuO2

We report the high-pressure synthesis of the electron-doped infinite-layer superconductor Sr0.9La0.1CuO2. A Rietveld analysis using X-ray powder diffraction data showed that, within the resolution of the measurement, the sample was purely an infinite-layer structure without any discernible impurities. The superconducting volume fraction and the transition width were greatly improved compared to those in the previous reports. Also the irreversibility field line was much higher than that of (La,Sr)2CuO4. The higher value seems to originate from the strong interlayer coupling due to the reduced average distance between the CuO2 planes.