Compressibilities and volume dependence of Tsub(c) for eleven Chevrel phase superconductors

Compressibility measurements up to 29.8 kbar (10 kbar = 1 GPa) are presented for a number of superconducting ternary molybdenum sulphides and selenides as well as the binary compound Mo6Se8. The percent volume change (ΔV/V0) exhibits a strong nonlinear dependence on applied pressure. Values of the bulk modulus (B0) and its first pressure derivative (B'0) are obtained by fitting these data to the Murnaghan equation of state. This analysis reveals a small bulk modulus for each material, with values comparable to those found in simple s-p elements such as indium. The data are also utilised to convert previously measured pressure effects on the superconducting transition temperature into the more physically meaningful volume dependence of Tsub(c). (author)