Electronic and Magnetic Properties of Europium-Intercalated Graphite

Stage-1 Eu-intercalated graphite Eu${\mathrm{C}}_6$ was studied by Mössbauer 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 $\overrightarrow{\mathrm{c}}$ and a magnetic hyperfine field saturating at - 10.7 T. The large electric field gradient at the Eu site (-1.4×${10}^{18}$ V/${\mathrm{cm}}^2$), with axis parallel to $\overrightarrow{\mathrm{c}}$, is consistent with the structure of Eu${\mathrm{C}}_6$ and a partial charge transfer from Eu to the C planes.