Pressure effects on FeSe family superconductors

We investigated the pressure effects on the FeSe superconductor and the related compounds. Pressure dependence of superconducting transition temperature (T-c) for FeSe0.8S0.2 exhibits a dome-shaped behavior below 0.76 GPa. On the other hand, the T-c of FeSe0.25Te0.75 linearly increases up to 0.99 GPa. Here we discuss the relation between the physical pressure effects and the chemical pressure effects on the FeSe system. (C) 2009 Published by Elsevier B.V.