Unification of the pressure and composition dependence of superconductivity in Ru substituted BaFe2As2

Temperature dependent high pressure electrical resistivity studies have been carried out on Ba(Fe1−x Rux)2As2 single crystals with x=0.12, 0.26 and 0.35, which correspond to under-doped, optimally doped and over-doped composition regimes, respectively. The evolution of structural/magnetic (TS–M) and superconducting transition (Tc) temperatures, with pressure for various compositions has been obtained. The normal state resistivity has been analyzed in terms of a model that incorporates both spin fluctuations and the opening of the gap in the spin density wave (SDW) phase. It is shown that Tc scales with the strength of the spin fluctuation, B, and TS–M scales with the SDW gap parameter, Δ. This provides a prescription for the unification of the composition and pressure induced superconductivity in BaFe2As2.