Fermiology of the Magnetic Superconductor Β″-(Bedt-ttf)4[(h2o)fe(c2o4)3].c6h5cn

The Fermi surface topology and electronic bandwidth of the first ever organic superconductor containing magnetic ions, the charge transfer salt β"-(BEDT-TTF)4[(H2O)Fe(C2O4)3].C6H5CN, have been studied using angle-dependent magnetoresistance oscillation (AMRO) and infrared (IR) reflectivity measurements. This material has a superconducting transition temperature of 7 K. AMRO data have been recorded at 1.4 K in a field of 15 T for all possible orientations of the sample with respect to the applied field. Several features with very strong azimuthal dependence are observed. The IR reflectivity is also very anisotropic; the reflectivity for E parallel to the needle axis is eight times greater than for the perpendicular direction. The results are discussed in relation to the calculated band structure and Fermi surface.