Researchers working to understand high temperature superconductivity in barium-iron-arsenide have discovered that applying pressure affects the material's magnetic and superconducting behavior just as if they had replaced some iron with a little ruthenium. To better quantify and understand the similarities of changing pressure versus ruthenium concentration, they made Ba(Fe1-xRux)2As2 with varying amounts (x) of ruthenium and studied each concentration as a function of pressure and temperature. The temperature-pressure phase diagrams showed this scaling is remarkably simple; every 3 GigaPascals of pressure, 30 times the pressure in the deepest part of the ocean, is roughly equivalent to replacing 10% of the iron with ruthenium. By comparing the various phase diagrams they were also able to show what is required for this material to reach its highest superconducting temperature.
Combined Effects of Pressure and Ru Substitution on BaFe2As2