Superexchange and magnetic relaxation in novel Eu-DOPED C60 phases
Résumé
EuxC6o compounds have been synthesized using high temperature solid-solid reaction. For x = 3 and 6 new crystalline structures appear. Mossbauer experiments reveal the simultaneous presence of Eu2+ and Eu3+ ions. In Eu6C60, ferromagnetic Eu pairs form at 65 K through a superexchange mechanism via the bucky balls. Higher clusters form at lower temperatures. In Eu3C60, relaxation effects can be related with the presence of an amorphous state.