Dislocation motions in C₆₀ crystals by an indentation test

We investigated dislocation motions in C-60 crystals after indentation, by x-ray topography and etching method. A rosette pattern was observed around an indentation after etching. The dislocations in the rosette were moved by thermal annealing and the positions in the dislocations were measured before and after annealing by the double etching method. The annealing temperature dependence of dislocation motions was measured in the temperature range 490-610 K. The characteristics of dislocation motion showed dislocation locking due to impurity atmosphere. It was concluded that oxygen and oxide of C60 molecules could lock the dislocations. Moreover, a pair of pits in the rosette pattern were observed after annealing. It corresponded to a pair of Shockley's partial dislocations.