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Abstract: We have studied the anisotropic superconducting properties of Sc5Ir4Si10 single crystalline sample by magnetic measurements. The upper critical field, H c2, for H parallel to the c-axis is larger than that for H parallel to the ab-plane, with the anisotropic parameter of about 2.3, indicating that Sc5Ir4Si10 is a quasi-one-dimensional superconductor. The magnetic penetration depths are estimated as λ c(0)=840Å and λ ab (0)=2100Å. The anisotropy of H c2 is also confirmed in randomly oriented powder samples. [Copyright &y& Elsevier]

Abstract: The effect of orientation on the creep properties of DD6 single crystal superalloy is investigated. The results show that anisotropic creep behaviors of DD6 alloy within 20° of the [001] direction are observed at 760°C and 785MPa. The [001] direction and the [001]–[011] boundary exhibit lower primary creep strain and longer creep rupture lives than the [001]–[111] boundary. In addition, the major creep deformation mechanism of DD6 single crystal superalloy at 760°C and 785MPa is a〈112〉 dislocation ribbon passing through both γ and γ′ phases. The interaction between 〈112〉{111} systems is the principle hardening mechanism for the transition from primary creep to secondary creep, the interaction leads to the anisotropy of primary creep and creep rupture lives for the [001] direction, the [001]–[011] boundary and the [001]–[011] boundary. [Copyright &y& Elsevier]

Abstract: Resistivities of polycrystalline iron-based NdFeAsO0.88F0.12 superconductors prepared via solid-state reaction in ambient pressure (AP) and high pressure (HP) were measured in various magnetic fields ranging from 0 to 9T. Different resistivity broadening behaviors of the AP and HP samples, which may originate from the anisotropic superconductivity, the vortex motion, or the connectivity, were investigated in detail. The effective pinning barriers of both the AP and HP samples were obtained from the Arrhenius plot of the resistivity data by two analytic methods of which one assuming the prefactor 2ρ c U/T of the thermally activated flux flow (TAFF) resistivity ρ=(2ρ c U/T)exp(−U/T) is a constant, while the other assuming the prefactor is temperature dependent. The results determined from the two methods were compared and analysed, and the true effective pinning barriers were obtained. The origin of different pinning barriers of the AP and HP samples is discussed. [Copyright &y& Elsevier]