Electronic and Magnetic Properties of Europium-Intercalated Graphite

Abstract

Stage-1 Eu-intercalated graphite Eu${\mathrm{C}}_{6}$ was studied by M\"ossbauer and $L$-edge spectroscopy. Isomer shift and ${L}_{\mathrm{III}}$-edge position results indicate the divalent state for Eu. Below 40 K, Eu${\mathrm{C}}_{6}$ orders antiferromagnetically with the Eu spins oriented perpendicular to $\stackrel{\ensuremath{\rightarrow}}{\mathrm{c}}$ and a magnetic hyperfine field saturating at - 10.7 T. The large electric field gradient at the Eu site (-1.4\ifmmode\times\else\texttimes\fi{}${10}^{18}$ V/${\mathrm{cm}}^{2}$), with axis parallel to $\stackrel{\ensuremath{\rightarrow}}{\mathrm{c}}$, is consistent with the structure of Eu${\mathrm{C}}_{6}$ and a partial charge transfer from Eu to the C planes.