The magnetism in SrFe2As2 can be suppressed by electron doping through a
small substitution of Fe by Co or Ni, giving way to superconductivity. We
demonstrate that a massive substitution of Fe by isovalent ruthenium similarly
suppresses the magnetic ordering in SrFe2-xRuxAs2 and leads to bulk
superconductivity for 0.6 <= x <= 0.8. Magnetization, electrical resistivity,
and specific heat data show Tc up to approx 20K. Detailed structural
investigations reveal a strong decrease of the lattice parameter ratio c/a with
increasing x. DFT band structure calculations are in line with the observation
that the magnetic order in SrFe2-xRuxAs2 is only destabilized for large x.Comment: 6 pages, 5 figures, extended and revised versio