Pressure tuning of the Se-substituted BiS2-based superconductor LaO0.5F0.5Bi(S 1 − x Se x )2

Abstract We report the effect of hydrostatic pressure on LaO 0.5 F 0.5 Bi(S 1 − x Se x ) 2 with chemical pressure applied to a conducting layer by means of electrical resistivity and ac-magnetic susceptibility measurements up to 2.5 GPa. We confirmed the bulk superconductive nature of the low superconducting (low-SC) and high superconducting (high-SC) phase using ac-magnetic susceptibility under hydrostatic pressure. The T c of the high-SC phase was observed to decrease with an increase in the Se substitution. The critical pressure P c shifted toward the higher P and the P -induced transition broadened with an increase in the Se content. The T c of the low-SC phase can be expressed by assuming an applied hydrostatic pressure of 0.75 GPa as the Se substitution of x = 0.1. The broad P c transition is likely to be ascribed to the inhomogeneity of the Se substitution.