engleski

Electrical Conductivity in Dynamically Orientationally Disordered Systems: ac and dc Measurements in Ferromagnetic Single Crystals of TDAE-C60

In spite of a metallic C-60 molecular ground state, electrical conductivity measurements performed on single crystals of ferromagnetic TDAE-C-60 fail to show evidence of metallic behavior. Instead, the material appears to be an insulter exhibiting conductivity of the form sigma(omega, T) = sigma(dc)(T) + sigma(ac) (omega). Phonon-assisted activated polaronic hopping and interbuckyball tunneling, respectively, are proposed as the mechanisms for the two processes. The transition from a dynamically disordered state (rotating buckyballs) to a quasiordered state (frozen buckyballs) is clearly visible as a change in activation energy in the conductivity at T-0 = 150 K.

FULLERENE ; RBC60

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