Journal Club do Departamento de Física dos Materiais e Mecânica

Among many two-dimensional (2D) high TC superconductors, graphite intercalation compounds (GICs)  are the most famous intercalation family, which are classified as typical electron-phonon mediated  superconductors. We show unambiguous experimental facts that BaC6, the superconductivity of which  has been missing for many years so far among various alkaline earth metal (Ca, Sr, and Ba) intercalted GICs,  exhibits superconductivity at Tc = 65 mK. By adding this finding as the additional experimental point, a  complete figure displaying the relationship between Tc and interlayer distance (d) for GICs is nowprovided,  and their possible superconducting mechanisms raised so far are revisited. The present study settles a
long-running debate between theories and experiments on the superconductivity in the first stage GICs.       

LaMn3Cr4Owith cubic symmetry is a novel spin-driven multiferroic system with strong magnetoelectric coupling effects. When a magnetic field is applied in parallel (perpendicular) to an electric field, the ferroelectric polarization can be enhanced (suppressed) significantly. The unique multiferroic phenomenon observed in this cubic perovskite cannot be understood by conventional spin-driven microscopic mechanisms. Instead, a nontrivial effect involving the interactions between two magnetic sublattices is likely to play a crucial role.