Effect of selenium doping on superconductivity in high-pressure synthesis T' structure Sm1.85Ce0.15CuO4

Selenium doped Sm1.85Ce0.15CuO4 was prepared at a high-temperature/high-pressure condition. The magnitudes of resistivity are decreased with increasing Se concentration in the samples. The superconductor was obtained at Se concentration x = 0.3 and required no additional reducing treating. We propose that selenium doping maybe produce SeO2 under high-pressure and provide a weak reducing environment to trigger superconducting. Result of XPS and XRD measurements on the sample supports this model