Antivortex paramagnetism in the magnetic-field-induced superconducting state of ${\mathrm{Eu}}_{\mathrm{x}}$${\mathrm{Sn}}_{1\mathrm{-}\mathrm{x}}$${\mathrm{Mo}}_6$${\mathrm{S}}_8$

It is shown that the magnetic-field-induced superconducting state recently observed in the system ${\mathrm{Eu}}_{\mathrm{x}}$ ${\mathrm{Sn}}_{1\mathrm{-}\mathrm{x}}$ ${\mathrm{Mo}}_6$ ${\mathrm{S}}_8$ has new and unexpected magnetic properties. In particular, for a certain applied field, the external field will penetrate completely and uniformly into the superconductor. Below this field the superconductor contains antivortices and the magnetic field is enhanced in the superconducting regions. A first observation of the paramagnetic nature of this state is presented.