  We report the high-pressure synthesis of the electron-doped infinite-layer
superconductor Sr0.9La0.1CuO2 and its superconducting properties. A Rietveld
analysis of X-ray powder diffraction data showed that, within the resolution of
the measurement, the sample had purely an infinite-layer structure without any
discernible impurities. The superconducting volume fraction and the transition
width were greatly improved compared to those in previous reports. The
irreversibility field line and the intragranular critical current density were
much higher than those of La1.85Sr0.15CuO4 and Nd1.85Ce0.15CuO4. The stronger
pinning behaviors are consistent with the strong interlayer coupling due to the
short distance between CuO2 planes.
