Neodymium-Doping Induced Superconductivity in 1111-SrFeAsF Iron-Pnictide System

摘要: Polycrystalline Sr1−x Nd x FeAsF samples at various Nd-doping levels have been prepared by conventional solid-state synthesis close to ambient pressure. Susceptibility and resistivity were studied down 4 K showing superconductivity competing with a low-temperature magnetic ordering probably the coexistence of both, well into superconducting region. The temperature dependence all Nd-doped clearly show presence this transition below 15 K, most likely originating from Nd moments. This is gradually attenuated but not completely suppressed even optimum-doping region x≈0.54. spin-density wave anomaly 175 K survives up 0.35 Nd-doping, while occurs only above x=0.40. maximum onset temperature, T c , reaches as high 54.3 K for x=0.70, disappears beyond that. estimated upper critical fields, H c2, are high, values exceeding 98 Tesla obtained two different doping level.