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Abstract

We report a pressure study on electron doped SrFe2-xCoxAs2 by electrical-resistivity (rho) and magnetic-susceptibility (chi) experiments. Application of either external pressure or Co substitution rapidly suppresses the spin-density wave ordering of the Fe moments and induces superconductivity in SrFe2As2. At x = 0.2 the broad superconducting (SC) dome in the T - p phase diagram exhibits its maximum T-c,T-max=20K at a pressure of only p(max) approximate to 0.75GPa. In SrFe1.5Co0.5As2 no superconductivity is observed anymore up to 2.8GPa. Upon increasing the Co concentration the maximum of the SC dome shifts toward lower pressure accompanied by a decrease in the value of T-c,T-max. Even though, superconductivity is induced by both tuning methods, Co substitution leads to a much more robust SC state. Our study evidences that in SrFe2-xCoxAs2 both, the effect of pressure and Co substitution, have to be considered in order to understand the SC phase-diagram and further attests the close relationship of SrFe2As2 and its sister compound BaFe2As2. (C) 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim