Superconductivity in Rh-doped CaFeAsF

Superconductivity was induced in polycrystalline CaFeAsF through doping with the 4d transition metal rhodium. The highest onset T-c achieved was approximately 25 K. We systematically studied the evolution of the resistivity in CaFe1-xRhxAsF for x ranging from 0 to 0.15. A phase diagram for the resistivity revealed a region where antiferromagnetic and superconducting transitions coexist. The effect of annealing on the transition width was also investigated, but no obvious enhancement was observed.