Pressure-induced superconductivity in Ba sub(0.5)Sr sub(0.5)Fe sub(2)As sub(2)

High-pressure electrical resistance measurements have been performed on single crystal Ba sub(0.5)Sr sub(0.5)Fe sub(2)As sub(2) platelets to pressures of 16 GPa and temperatures down to 10 K using designer diamond anvils under quasi-hydrostatic conditions with an insulating steatite pressure medium. The resistance measurements show evidence of pressure-induced superconductivity with an onset transition temperature at ~31 K and zero resistance at ~22 K for a pressure of 3.3 GPa. The transition temperature decreases gradually with increasing pressure before completely disappearing for pressures above 12 GPa. The present results provide experimental evidence that a solid solution of two 122-type materials, i.e., Ba sub(1-x)Sr sub(x)Fe sub(2)As sub(2) (0 < x < 1), can also exhibit superconductivity under high pressure.