Observation of Bulk Superconductivity in EuMo6S8under Pressure

The upper critical magnetic field of Eu${\mathrm{Mo}}_6$ ${\mathrm{S}}_8$ in its high-pressure superconducting phase was measured resistively at 16 kbar in dc magnetic fields to 28 T. The data can be described by multiple pair-breaking theory including a negative exchange field due to the ${\mathrm{Eu}}^{2+}$ ions that acts on the superconducting electrons. Measurements of the ac heat capacity of Eu${\mathrm{Mo}}_6$ ${\mathrm{S}}_8$ above ∼ 13 kbar revealed that the compound exhibits bulk superconductivity, but no Meissner effect was observed in magnetization measurements.