Study of volume superconductivity in β-(ET)₂X superconductors

We have shown by DC low field magnetisation measurements the existence of diamagnetic shielding and Meissner signals in the ambient pressure organic superconductors, β-ET2X (X = IBr2 and AuI2), below T = 2.5 K and T = 4.1 K, respectively. This proves that superconductivity is a volume property in these compounds. The low field data, together with values of the upper critical field Hc2, yield a thermodynamically consistent picture within the framework of the Ginzburg-Landau theory for the β-ET2IBr2 and β-ET2AuI2 compounds. © 1987.