Effects of Mechanical Grinding on C60And Ca5C60Superconductor

摘要

The effects of mechanical grinding on polycrystalline C60and Ca5C60superconductor are examined. It has been found that mechanical grinding may severely degrade phases of C60(fcc) and Ca5C60(sc). The grinding destroys the long-range ordering of crystals and produces a partial amorphous state. The damage of crystal leads to the disappearance of superconductivity for Ca5C60. The samples with an amorphous phase can be recrystallized by annealing at 600#xB0;C for pure C60and Ca5C60. Magnetic susceptibility measurements indicated that the superconductivity of the degraded sample did not recover easily to the initial state.